prefix, from various sources.
1. OE. and ME. an-, = AN prep. (see prec.) In OE. the orig. an- remained only under the stress, i.e., in sbs.; otherwise, it was, like the separate preposition, rounded to on-; thus a·ngin beginning, ongi·nnan to begin, onbú·tan about. An example of the former remains in ANVIL. In ME. on- was regularly levelled to ă- (A- pref. 2); before a vowel (rarely bef. cons.) ăn-, as in anelen, aninne, anoven, anunder, anuppe, anhigh, anblow, anlike. Most of these are now obs.; a few remain with an- conformed to the prep. on, as on high; levelled to a- as alike; or assimilated to Fr. en-, as (?) enamel. Only where the individuality of the prefix has been lost, does an- remain, in anon, anent, an(n)eal (OE. on-ǽlan, ME. an-ele(n).
2. ME. an-, reduced f. OE. and- ‘against, towards, in return for’: see AND-.
3. ME. an-:—OE. án one, retained in early ME., and subseq. in north. dial., in words now written with on-, one-, or obs.; as ankenned, anfald, anhad, anlepy, anly (= ONLY), anmod, anred, anwill.
4. ME. an-, = Anglo-Norm. an-, OFr. en-:—L. in-, = ‘in, into,’ as ANOINT (L. inunctum), AN(N)OY; anhaunse, anjoin, anvenime, where subsequently spelt en-; andetted, subseq. endetted, indebted; anpayre, subseq. apayre, also enpayre, empayre, impair.
5. ME. an-, for earlier a- = OE. a- (A- pref. 1), or OFr. a-:—L. ab-, ad-, ex-, ob-, which, being phonetically identified with No. 1 above, was like it expanded to an- bef. vowels, and occas. bef. consonants: as in a(n)chesoun = oc-casion, a(n)ferm af-firm, a(n)ired, a(n)oure ad-ore, a(n)orn ad-orn, a(n)tempered at-tempered; a(n)s-aumple ex-ample. Such of these as survived were either refashioned after L., as adorn, or changed an- to en-, in-, as inorn; example, ensample, shows both processes.
6. ME. an-, a later spelling of earlier a-, = OFr. a-:—L. an- assimilated form of ad- ‘to,’ when followed by n-, after L. forms or supposed analogies, as in a(n)nounce. This doubling of the n began in 14th c. Fr. and extended to Eng. in 15th c. In 16th c. it was ignorantly extended even to words containing an- from other sources, from which it has generally been again ejected exc. in ANNEAL, ANNOY. See AD-.
7. an-, repr. L. an- = ad- before n-, in words derived from L. directly, or indirectly through later Fr., and in words formed on the analogy of them, as an-nex, an-nul, an-nunciation.
8. an-, repr. L. an- before certain consonants, for am-, amb-, ambi- ‘on both sides, about.’ Through OFr. in an-(h)ele; directly from L. in an-cipitous, an-fractuous.
9. an-, repr. Gr. ἀν- for ἀνά ‘up, upwards, back, etc.’ (see ANA-) bef. vowel, as in an-agoge, Gr. ἀναγωγή; also in an-chor2, an-choret.
10. an-, repr. Gr. ἀν- privative, ‘not, without, wanting’ (reduced before consonants to ἀ-: see A- pref. 14), cognate w. Skr. an-, L. in-, Eng. un-, ‘not, non-.’ In words already formed in Greek as an-archy, an-arthrous; whence common in modern scientific words as an-allagmatic, an-alphabetic, an-antherous, an-isomerous.
