Meaning of A- in English
a reduced form of the Old English preposition on, meaning "on," "in," "into," "to," "toward," preserved before a noun in a prepositional phrase, forming a predicate adjective or an adverbial element ( afoot; abed; ashore; aside; away ), or before an adjective ( afar; aloud; alow ), as a moribund prefix with a verb ( acknowledge ), and in archaic and dialectal use before a present participle in -ing ( set the bells aringing ); and added to a verb stem with the force of a present participle ( ablaze; agape; aglow; astride; and originally, awry ).
[ ME, late OE; cf. A 2 , NOWADAYS ]
a reduced form of the Old English preposition of: akin; afresh; anew.
[ ME; see A 3 ]
an old point-action prefix, not referring to an act as a whole, but only to the beginning or end: She arose (rose up). They abided by their beliefs (remained faithful to the end).
[ ME; OE a- (unstressed), ae-, a-, o- (stressed; see ABB, WOOF 1 , OAKUM), rarely or- (see ORDEAL) uz- uss- ud-s, akin to OUT; in some cases confused with A- 4 , as in ABRIDGE ]
var. of ab- before p and v: aperient; avert.
[ ME a-, a- (var. of ab- AB-); in some words a- ab-, as in ABRIDGE ]
var. of ad- , used: (1) before sc, sp, st ( ascend ) and (2) in words of French derivation (often with the sense of increase, addition): amass.
[ ME, in some words a- ad- prefix or ad prep. (see AD-), as in ABUT; in others a- (var. of ad- AD-), as in ASCEND ]
var. of an- 1 before a consonant, meaning "not," "without": amoral; atonal; achromatic.
Random House Webster's Unabridged English dictionary. Полный английский словарь Вебстер - Random House . 2012