Emily Dickinson Lexicon

a (an), article. [OE án, one; see one, adj.] Any; some; non-specific; one of many possible; indicating general membership in a class of entities; indefinite determiner.

1. [The form “a” appears preceding words that begin with a consonant.]
2. [The form “an” appears preceding words that begin with a vowel.]
3. [To indicate a special or geographical direction.] Phrase. “A little … of.”
4. [To indicate a unit of time.] Phrase. “A little while.”
5. Any.