prepositional prefix in composition with verbs, nouns and adjj. GOI 502.4 . Bergin, Ériu xiv 153 . In verbs in pretonic position con- (con-icc, con-gaib), with inf. pron. cotam-, cot-, conid-, etc. ( GOI 257 - 8 , 503 ). See also s. 5 con-.

Under the accent the treatment is as follows. Before vowels and r, l, n com, cum (under infl. of follg. sound) (comadas, comerchloithe, comimmaircide (earlier coímm- < com-imm-, see below), comocus s.v. com(ḟ)ocus, comrád, comlann, comnart, cumsanad). com-imm- gives coímm- ( GOI 112 , 502 ) (coímchloud, coímthecht s.v. coimitecht). Before b com (combach), before d, g con (condalb, coindelg, congab, congnam. Note later lenition of g in coingell, coinglecc and the artificial comglenn in Ml.). Before t, c co, cu with voicing of follg. plosive (cotach, cotarsnae, coitreb, cocad, cocur, coicéile, coicert, cutrummae. Note the artificial comchlante in Sg.). Before s co (cosmail, cosnam). Before f (earlier *w) co (cóir), later cob cub (cobair, cobodail, cubaid, cubus, cobfolaid, cobfuil). Before m cu (cuman), later cum, com (cummasc, commess).

Later co(i)m is used as the general form before all initials (see exx. under coim-, 1 com-), both the m and a follg. initial c p t d g r l n f s being lenited. Before b, m the older procedure is retained, mb ultimately falling together with mm to give m(m). But where the elements in a compd. remain clear and in late formations -mb- (-mmb-, mhmb-, -mbb- -mhbh-) is usually retained (combádud, combág, combáid, combráithres, combroid). So also somet. mhm (mhmh) for mm (commaídem, commaídid, commám).

In the early language the neutral quality of final -m was retained before palatals (comnart, congnam, cosnam, with re-composition comnert, comgním. Cf. coicéile comchéile, comlann comlán comlín). Palatalization is later regular in this position (coimchrith coimescar). Where com was itself modified palatalization came in earlier (coicert, cuitbiud, cuindchid, cuimrech etc.).

In old verbal compounds (con-dieig, con-icc) the semantic function of com can as a rule only be conjectured. In later formations with verbs (coimlenaid) and with adjj. com has the adverbial force of together, mutually, equally , with nouns the adjectival force of mutual, equal . The last-mentioned are frequent in g s. with adjectival function (comchenél), the type comnart strong being rare. In all late compds. com may function as a mere intensive prefix greatly, very, completely, great, complete etc. Frequently the prefix serves merely to provide an alliterating word. For com with adjj. forming the equative see 2 com-.