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Word
English Vocabulary
Pick a CEFR level (A1–C2, plus C2+ for rare words beyond the CEFR scale) — A1 is the friendliest place to start — and browse its words grouped by topic: travel, food, the body, emotions, and more. Each word shows its meaning, example sentences, and US/UK pronunciation.
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All 27,899 wordsC2+ is beyond the official CEFR scale: rare, specialist, and literary words kept for reference.
117 words
science
A1
/ˈsaɪ.əns/
The study of the physical world through observation and experiment, covering subjects like physics, chemistry, and biology.
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research
A2
/ˈrisɚtʃ/
A careful study to discover new facts or information.
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theory
B1
/ˈθɪ.ɹi/
A set of ideas that explains how or why something happens, supported by evidence.
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data
A2
/ˈdeɪtə/
Facts and figures collected for analysis or to draw conclusions.
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experiment
B1
/ɪkˈspɛɹ.ə.mənt/
A scientific test done to discover something or to check whether an idea is true.
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scientific
A2
/ˌsaɪənˈtɪfɪk/
Relating to science or the way science is done.
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discovery
B1
/dɪsˈkʌv(.ə).ɹi/
Something that is found or learned for the first time.
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analysis
B1
/əˈnæl.ə.sɪs/
The careful study of something by examining its parts in detail.
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engineering
B1
/ˌɛn.d͡ʒɪˈnɪ(ə)ɹ.ɪŋ/
The work of using science and maths to design and build machines, structures, and systems.
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mutant
C2
/ˈmjuː.tənt/
an organism, cell, gene, or other biological entity that carries a mutation
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uranium
B2
/ˌjuːˈɹeɪniəm/
The element with atomic number 92 and symbol U. A radioactive silvery-grey metal in the actinide series.
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hypothesis
C2
[haɪˈpʰɑθəsɪs]
An idea put forward to explain something, which can then be tested.
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helium
C1
/ˈhiː.li.əm/
a very light, colorless, and odorless element that is one of the six inert gasses
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silicon
B2
/ˈsɪl.ə.kən/
the chemical element with symbol Si and atomic number 14, a hard, brittle semiconductor abundant in rocks as silica and silicates and widely used in electronic devices
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arsenic
C2
/ˈɑɹsənɪk/
a very poisonous metallic element that has three allotropic forms
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plutonium
C2
/pluːˈtoʊniəm/
The transuranic chemical element with atomic number 94 and symbol Pu: a silvery-gray fissile radioactive actinide metal that tarnishes when exposed to air.
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geology
B1
/d͡ʒiˈɑ.lə.dʒi/
The science that studies the structure of the earth and its rocks.
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lithium
C1
/ˈlɪθ.i.əm/
the chemical element with symbol Li and atomic number 3, a soft, silvery-white, highly reactive alkali metal and the lightest metal
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iodine
C1
/ˈaɪəˌdaɪn/
the chemical element with atomic number 53, a dark halogen that forms a violet vapor when heated
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prism
C1
/ˈprɪzəm/
a transparent optical element with flat faces that refracts light, often separating it into colors
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brimstone
C2
/ˈbɹɪmstoʊn/
An old name for the element sulfur.
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cobalt
C1
/ˈkoʊbɔlt/
the chemical element with atomic number 27, a hard silvery-blue metal used in alloys, batteries, magnets, and pigments
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infusion
C1
/ɪnˈfjuːʒən/
the introduction of a new element, quality, or resource that changes or strengthens something
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hydraulics
B2
/haɪˈdrɑː.lɪks/
the science and engineering of liquids in motion and their use to transmit force
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stimuli
C1
/ˈstɪm.jʊˌlaɪ̯/
Things that cause a reaction or response in people, animals, or things (plural of stimulus)
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phosphorus
B2
/ˈfɑs.fɚ.əs/
A chemical element (symbol P) with an atomic number of 15, that exists in several allotropic forms.
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radium
B2
/ˈɹeɪ.di.əm/
A radioactive metal element (symbol Ra) that glows and was once used in medicine.
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iridium
C2
/ɪˈɹɪd.i.əm/
a chemical element (symbol Ir) with an atomic number of 77: a very hard, brittle, silvery-white transition metal of the platinum group.
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forestry
B2
/ˈfɒɹ.ɪst.ɹi/
The science and work of planting and looking after forests.
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argon
C2
/ˈɑːr.ɡɑːn/
the chemical element with symbol Ar and atomic number 18, a colorless, odorless, largely unreactive noble gas that forms about 0.93 percent of Earth's atmosphere
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barium
C1
/ˈbɛriːəm/
a soft silvery metallic element of the alkali earth group
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amoeba
C2
/əˈmiː.bə/
a single-celled organism that changes shape and moves or feeds by extending pseudopodia
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fluoride
C2
/ˈflɔːr.aɪd/
a compound in which fluorine is combined with a more electropositive element or chemical group
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hermaphrodite
C2
/hɝˈmæfɹədaɪt/
Cosexual: an organism possessing both types of gonads; a flower possessing both stamens and pistils.
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graviton
C2
/ˈɡræv.ɪˌtɑːn/
a hypothetical massless spin-2 boson that would be the quantum carrier of gravity in a quantum theory of the gravitational field
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chromium
C1
/ˈkroʊ.mi.əm/
the chemical element with atomic number 24 and symbol Cr, a hard, lustrous metal used especially in alloys and protective plating
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manganese
B2
/ˈmæŋɡəˌniːz/
the chemical element with atomic number 25, a hard gray metal used especially to strengthen steel and in batteries
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quicksilver
C2
/ˈkwɪkˌsɪlvɚ/
the metallic element mercury, especially when seen in its mobile liquid form
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jurisprudence
C2
/ˌdʒʊr.ɪsˈpruː.dəns/
the theory or philosophy of law and the principles by which legal systems interpret and apply it
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beryllium
C2
/bəˈrɪl.i.əm/
the chemical element with symbol Be and atomic number 4, a hard, gray, low-density alkaline-earth metal valued for its stiffness and transparency to X-rays
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morphology
B2
/mɔɹˈfɑ.lə.d͡ʒi/
the branch of biology that deals with the structure of animals and plants
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metallurgy
C2
/ˈmɛt.əˌlɝ.dʒi/
the science and technology of extracting metals, refining and alloying them, and controlling their properties during processing
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ism
C2
/ˈɪz.əm/
a distinctive doctrine, theory, cause, or movement, especially one named with the suffix -ism
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fluorine
C2
/ˈflɔːr.iːn/
the chemical element with symbol F and atomic number 9, whose elemental form is an extremely reactive, toxic, pale-yellow halogen gas
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thorium
C2
/ˈθɔːɹiəm/
a soft silvery-white tetravalent radioactive metallic element
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jurist
C2
/ˈdʒʊr.ɪst/
an expert or scholar in law and legal theory
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silicate
C2
/ˈsɪlɪkət/
chemistry: a salt or ester derived from a silicic acid and containing silicon and oxygen
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experimenter
B2
/ɪkˈsper.əˌmen.tɚ/
a scientist or researcher who conducts an experiment
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bismuth
C2
/ˈbɪz.məθ/
the chemical element with symbol Bi and atomic number 83, a dense, brittle, crystalline metal that is silvery white with a pink tinge
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interbreeding
B2
/ˌɪntɚˈbriːdɪŋ/
reproduction between animals or plants from different populations, breeds, varieties, or closely related species
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gallium
C1
/ˈɡæliəm/
a chemical element (symbol Ga) with an atomic number of 31; a soft bluish metal.
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vanadium
C2
/vəˈneɪ.di.əm/
the chemical element with symbol V and atomic number 23, a silvery transition metal used chiefly to strengthen steel and in several industrial catalysts
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bromine
C2
/ˈbroʊ.miːn/
the chemical element with atomic number 35 and symbol Br, a toxic, fuming red-brown halogen that is liquid at room temperature
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promethium
C2
/prəˈmiː.θi.əm/
the radioactive rare-earth chemical element with symbol Pm and atomic number 61, which has no stable isotopes
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atavism
C2
/ˈætəˌvɪzəm/
the reappearance in an organism of a trait associated with a remote ancestor
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utilitarianism
C2
/ˌjuːtɪlɪˈteriənɪzəm/
the ethical theory that the best action is the one that produces the greatest overall well-being or happiness
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epistemology
C2
/ɪˌpɪstəˈmɑləd͡ʒi/
The branch of philosophy dealing with the study of knowledge; the theory of knowledge, asking such questions as "What is knowledge?", "How is knowledge acquired?", "What do people know?", "How do we know what we know?", "How do we know it is true?", and so on.
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radioisotope
C2
/ˌreɪ.di.oʊˈaɪ.sə.toʊp/
a radioactive isotope of an element, whose unstable nuclei decay and emit radiation
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actinium
C2
/ækˈtɪn.i.əm/
the radioactive metallic chemical element with symbol Ac and atomic number 89, the first element of the actinide series
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agriculturist
C2
/ˌæɡrɪˈkʌltʃərɪst/
a specialist trained in the science, practice, or management of agriculture
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embryology
C2
/ˌɛmbriːˈɑːlədʒi/
the branch of biology that studies the formation and early development of living organisms
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mendelevium
C2+
/ˌmɛn.dəˈli.vi.əm/
a synthetic radioactive metallic chemical element with atomic number 101 and symbol Md
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sensorium
C2
/sɛnˈsoɹ.i.jəm/
The entire sensory apparatus of an organism.
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technetium
C2
/tɛkˈniː.ʃi.əm/
the radioactive metallic chemical element with symbol Tc and atomic number 43, all of whose isotopes are unstable
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vesicle
C2
/ˈvɛsɪkəl/
a small membrane-bound sac or cavity in a cell or organism, often containing fluid or another substance
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plasm
C2
/ˈplæzəm/
biology, now rare: the living substance of a cell; protoplasm
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neptunium
C2
/nɛpˈtjuːniəm/
the radioactive transuranic chemical element with symbol Np and atomic number 93
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hermaphroditism
C2
/hɚˈmæfɹədaɪˌtɪzəm/
in biology, the condition of having both male and female reproductive organs, either simultaneously or at different life stages
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protactinium
C2
/ˌproʊ.tækˈtɪn.i.əm/
the chemical element with symbol Pa and atomic number 91, a dense, silvery, highly radioactive actinide metal with no stable isotopes
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integument
C2
/ˌɪnˈtɛɡ.jə.mənt/
a natural outer covering that protects an organism or one of its parts, such as skin, a shell, or a seed coat
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curium
C2
/ˈkjʊə.ɹi.əm/
a synthetic radioactive metallic chemical element with atomic number 96 and symbol Cm
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dietetics
C2
/ˌdaɪəˈtɛtɪks/
the science and professional practice of planning diets in relation to health and disease
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sequent
C2
/ˈsiː.kwənt/
in proof theory, a formal expression showing that one or more conclusion formulas follow from a collection of premise formulas
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einsteinium
C1
/aɪnˈstaɪni.əm/
a synthetic radioactive chemical element with atomic number 99 and symbol Es
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fermium
C2
/ˈfɜːɹmiəm/
a synthetic radioactive chemical element with atomic number 100 and symbol Fm
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filum
C2
/ˈfaɪləm/
anatomy and biology: a slender thread-like structure or filament
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protozoon
C2
/ˌproʊtəˈzoʊɑn/
dated: a single protozoan organism; one of the mostly microscopic unicellular organisms formerly grouped as Protozoa
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conversazione
C2
/ˌkɑnvɚsɑtsiˈoʊni/
a formal social gathering devoted to discussion of literature, art, science, or another learned subject
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lawrencium
C2
/ləˈɹɛnsiəm/
a synthetic radioactive chemical element with atomic number 103 and symbol Lr
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heterozygote
C2
/ˌhet̬.ə.roʊˈzaɪ.ɡoʊt/
an organism or cell having two different alleles at a particular gene locus
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homozygote
C2
/ˌhoʊmoʊˈzaɪɡoʊt/
an organism or cell with two identical alleles at a specified genetic locus
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pangenesis
C2
/ˌpænˈdʒɛnəsɪs/
Darwin's disproved hypothesis that every part of an organism releases hereditary particles which collect in reproductive cells and can be passed to offspring
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monadology
C2
/ˌmɑnəˈdɑlədʒi/
a metaphysical doctrine or study of monads, especially Leibniz's theory that reality consists of simple immaterial substances
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rutherfordium
C2+
/ˌɹʌðəɹˈfɔːɹdiəm/
a synthetic radioactive chemical element with atomic number 104 and symbol Rf
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empiric
C2+
/ɪmˈpɪrɪk/
one who relies on observation or experiment; an unqualified practitioner
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mechanics
C2+
/məˈkænɪks/
the science of motion and forces; the practical workings of something
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photoperiod
C2+
/ˌfoʊtoʊˈpɪriəd/
the duration of daily light exposure affecting an organism
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soma
C2+
/ˈsoʊmə/
the body of an organism as distinct from its germ cells or psyche
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alchemy
C2+
/ˈælkəmi/
the medieval forerunner of chemistry seeking to transmute metals into gold
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axiomatization
C2+
/ˌæksiəmətəˈzeɪʃən/
the formulation of a theory as a set of axioms from which theorems derive
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behaviorism
C2+
/bɪˈheɪvjəˌrɪzəm/
the psychological theory that behavior can be explained by conditioning
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cartography
C2+
/kɑrˈtɑɡrəfi/
the science and art of making maps
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horticulture
C2+
/ˈhɔrtəˌkʌltʃɚ/
the art and science of cultivating gardens, fruits, vegetables, and flowers
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hygienics
C2+
/haɪˈdʒɛnɪks/
the science or principles of hygiene and the preservation of health
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mutualist
C2+
/ˈmjutʃuəlɪst/
an advocate of mutualism, or an organism in a mutual relationship
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poetics
C2+
/poʊˈɛtɪks/
the study or theory of the principles and forms of poetry and literature
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