LSJ
ἡ, stopping of a hiatus, coalescing of two syllables into one, either by synaeresis, crasis, or elision, D.H. Comp. 6, 22, al., S.E. M. 1.161; κατὰ συναλιφὴν τοῦ ἄρθρου (in ὦλλοι) A.D. Synt. 5.28; τῆς σ. Ἰωνικωτέρας γενομένης (in ὑπόδρα for ὑφ-) Id. Adv. 139.14, cf. 152.20; Eust. 1561.6 speaks only of crasis and synaeresis; κατὰ τὴν σ. Str. 8.6.7; = coeuntes litterae, Quint. Inst. 9.4.35; generally, running together of words, Demetr. Eloc. 70. = νουμηνία, Gem. 8.11. [In codd. freq. written συναλειφή (e.g. Sch. All. 24.12) or συναλοιφή, but -αλιφ-, which is mentioned by Eust. 1561.6, is found in the best codd. of D.H. Comp. ll.cc., A.D. Synt. 140.14 (v. Uhlig ad loc.), al., Heph. 2.4, Suid. s.v. ἔνθους, ἕνωσις, Sch. A Il. passim, EM 116.23, al. (v. p. 2464 Gaisf.), Sch. S. OC 504, 1588, Sch. E. Hec. 336; cf. ἀλιφή, ἀπαλοιφή, καταλιφή, περιαλιφή.]
Liddell-Scott-Jones, Greek-English Lexicon (9th ed., 1940)