a

Meanings

1. 1
   noun

   the unit symbol for the ampere, the basic unit of electric current adopted under the Systeme International d'Unites

   My headlights have a current of 5 A each.

2. 2
   noun

   short form for adenine, a purine base found in DNA and RNA

   I used 2mg of A in the experiment.

3. 3
   noun

   one of the four nucleotides used in building DNA

   My DNA gene sequence had 3,000 As in it.

4. 4
   noun

   any of several fat-soluble vitamins essential for normal vision

   Did you get your daily dose of A today?

5. 5
   det

   the indefinite article, used to non-specifically identify something

   I chose a shirt from the closet.

6. 6
   noun

   the 1st letter of the Roman alphabet

   My name contains the letter a.

7. 7
   character

   The first letter of the English alphabet, called a and written in the Latin script.

   Apple starts with A.

8. 8
   num

   The first numeral symbol of the English alphabet, called a and written in the Latin script.

   Item A is "foods", item B is "drinks".

Etymology

Etymology tree Proto-Indo-European *ís? Proto-Indo-European *h₁óynos Proto-Germanic *ainaz Proto-West Germanic *ain Old English ān Middle English an Middle English a English a From Middle English a, an, from Old English ān (“one; a; lone; sole”). More at one. The "n" was gradually lost before consonants in almost all dialects by the 15th century. Cognate with Alemannic German a (“a, an”), East Franconian a (“a, an”).