εἰσβολή · eisbolē — LSJ
inroad, invasion, Hdt. 6.92, E. Ion 722 (lyr.), etc.; ποταμῶν Plb. 4.40.9; διὰ τὴν ἐς Σάρδις ἐσβολήν Hdt. 7.1; ἐ. ποιεῖσθαι τῇ πόλει Th. 8.31 codd.; irruption of false opinions, Polystr. p.19 W.; of an illness, attack, Aret. SD 2.12, CA 1.1.
entrance, pass, ἐ. ἐξ ὀρέων στεινῶν ἐς πεδίον Hdt. 2.75; ἡ ἐ. ἡ Ὀλυμπική the pass of Mount Olympus, Id. 7.172, cf. Th. 3.112; Συμπληγάδων ἐ. E. Med. 1264 (lyr.): pl., of Thermopylae, Hdt. 7.176, cf. 1.185, 2.141, Jul. Or. 2.98b.
pl., mouth of a river, v.l. for ἐκβ. in Hdt. 7.182.
entering upon a thing, beginning, καινὰς ἐσβολὰς ὁρῶ λόγων E. Supp. 92; ἐ. στεναγμάτων Id. Ion 677 (lyr.); σοφισμάτων Ar. Ra. 1104; κανόνων ib. 956; proem, preface, of a play, Antiph. 191.20, cf. D.H. Lys. 17 (pl.), Longin. 38.2.