Longman Dictionary of Contemporary English
The Collaborative International Dictionary
A- \A-\ A, as a prefix to English words, is derived from various sources. (1) It frequently signifies on or in (from an, a forms of AS. on), denoting a state, as in afoot, on foot, abed, amiss, asleep, aground, aloft, away (AS. onweg), and analogically, ablaze, atremble, etc. (2) AS. of off, from, as in adown (AS. ofd[=u]ne off the dun or hill). (3) AS. [=a]- (Goth. us-, ur-, Ger. er-), usually giving an intensive force, and sometimes the sense of away, on, back, as in arise, abide, ago. (4) Old English y- or i- (corrupted from the AS. inseparable particle ge-, cognate with OHG. ga-, gi-, Goth. ga-), which, as a prefix, made no essential addition to the meaning, as in aware. (5) French [`a] (L. ad to), as in abase, achieve. (6) L. a, ab, abs, from, as in avert. (7) Greek insep. prefix [alpha] without, or privative, not, as in abyss, atheist; akin to E. un-.
Note: Besides these, there are other sources from which the prefix a takes its origin.
Douglas Harper's Etymology Dictionary
in native (derived from Old English) words, it most commonly represents Old English an "on" (see a (2)), as in alive, asleep, abroad, afoot, etc., forming adjectives and adverbs from nouns; but it also can be Middle English of, as in anew, abreast (1590s); or a reduced form of Old English past participle prefix ge-, as in aware; or the Old English intensive a-, as in arise, awake, ashame, marking a verb as momentary, a single event. In words from Romanic languages, often it represents Latin ad- "to, at."[I]t naturally happened that all these a- prefixes were at length confusedly lumped together in idea, and the resultant a- looked upon as vaguely intensive, rhetorical, euphonic, or even archaic, and wholly otiose. [OED]
prefix meaning "not," from Greek a-, an- "not," from PIE root *ne "not" (see un-).
alt. academic grade issued by some institutions, which is inferior to an A and superior to a B+. n. academic grade issued by some institutions, which is inferior to an A and superior to a B+.
A- or a- may refer to:A-hyphen
- A- (plane), a U.S. military aircraft prefix
- Privative a, a prefix expressing negation
- Copulative a, a prefix expressing unification
- A-, a blood type in the ABO blood group system
- A- (grade), an educational grade in the letter-grading system, above B+ but below A