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/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 / without, or privative, not, as in abyss, atheist; akin to e. un-.