irrational B2 Topic:Numbers & Quantity US /ɪˈɹæʃ.(ə.)nəl/ See IPA manual Freq #11587 Meanings 1 adj Not based on clear thinking or good reasons He has an irrational fear of spiders. 2 adj In maths, describing a number that cannot be written as a simple fraction The number pi is irrational. 3 noun In maths, a number that cannot be written as a fraction of two whole numbers The square root of two was the first irrational the Greeks discovered. Thesaurus Synonyms 3 noun · in maths, a number that... irrational number Word family Derived forms irrationalismirrationalistirrationalisticirrationalityirrationalizationirrationalizeirrationallyirrationalnessnonirrational Common collocations irrational number Adjective + noun Etymology AI details From Latin irratiōnālis, from ir- + ratiōnālis. irratiōnālis Latin View etymology graph -> Topics Numbers & Quantity External links Cambridge Dictionary Wiktionary Google Images # irrational **Type:** Word **Level:** B2 **Part of speech:** adj, noun **IPA (US):** /ɪˈɹæʃ.(ə.)nəl/ **Frequency rank:** 11587 ## Meanings 1. Not based on clear thinking or good reasons 2. In maths, describing a number that cannot be written as a simple fraction 3. In maths, a number that cannot be written as a fraction of two whole numbers ## Examples - He has an irrational fear of spiders. - The number pi is irrational. - The square root of two was the first irrational the Greeks discovered. ## Derived Forms - irrationalism - irrationalist - irrationalistic - irrationality - irrationalization - irrationalize - irrationally - irrationalness - nonirrational ## Roots and Affixes - Root: irratiōnālis - Affix: ir- - not ## Etymology From Latin irratiōnālis, from ir- + ratiōnālis. ## AI Etymology Irrational comes from Latin irratiōnālis, from ir- + ratiōnālis. The analysis is mainly morphological: the modern adjectival form is built from the named base and affix. ## Topics - Numbers & Quantity markdown