The best account of these is to be found in Kellner's edition of Dr Morris's Historical Outlines of English Accidence (1895), and especially in Professor Skeat's Principles of English Etymology—First Series (2d ed. 1892), chaps. xii.-xiv.; Second Series (1891), chap. xviii. To these books the following lists are largely indebted.
A- (A.S.) represents:
(1) A.S. an, on, on, as abed, aboard, afoot, ashore, asunder, now-a-days, twice-a-week, alive, among, about, a-fishing.
(2) A.S. and-, over against, in reply to, to, as along (from A.S. and-lang, i.e. over against in length); appearing also as e- in elope, as am- in ambassador, and as em- in embassy; the same as un- in verbs. See Un- (2). [Cog. with Goth. and-, Ger. ent-, ant-, L. ante-, Gr. anti-.]
(3) A.S. á-, an intensive prefix to verbs, out, out from, as in arise (from A.S. árísan, to rise out of or up); or sig. 'very,' as in aghast. Cf. abide, accurse, affright, amaze, arise, arouse, ago. [Cog. with Ger. er-, Goth. us-, ur-.]
(4) A.S. of, of, from, as in adown (from A.S. of dúne, 'from the height'), anew, akin; or from of-, intensive, as athirst.
(5) A.S. ge-, y-, as aware (A.S. ge-wǽre), afford.
(6) at, old sign of inf., as ado. [A Northern idiom, due to Scand. influences, as in Ice., Sw., &c.]
A- (L. and Gr.) represents: (1) L. Ab-, as in avert; (2) L. Ad-, as achieve; (3) L. E- or Ex-, as in abash, amend; (4) Gr. A- (for An-), as in abyss. See these prefixes.