ἴς · is — LSJ
sinew, tendon, sg. once in Hom., ὡς δʼ ὅτʼ ἂν . . ἀνὴρ . . ἶνα τάμῃ διὰ πᾶσαν Il. 17.522: usu. in pl., sinews, οὐ γὰρ ἔτι σάρκας τε καὶ ὀστέα ἲνες ἔχουσιν Od. 11.219, cf. Il. 23.191; ἶνες ἄρθρων Ar. Pax 86, cf. Archil. 138; ἶνες αὐτὸ μόνον καὶ λεπτὴ δορά, of a person wasted by disease, Ph. 2.432; δοράς, σάρκας, ἶνας ib. 527: metaph., Τρωίας ἶνας ἐκταμὼν δορί Pi. I. 8(7).57.
later, the fibrous vessels in the muscles, Pl. Ti. 84a, Arist. HA 515b27, al.; in blood, fibrine, Id. PA 650b14, cf. Pl. Ti. 82c, Meno Iatr. 17.34: metaph., of metals, Plu. Def.orac. 2.434b.
rib in the leaves of plants, Thphr. HP 3.12.7 (sg.).
strip of papyrus, ταῖς τῶν χαρτῶν ἰσίν Sor. 1.13: sg., Gal. 10.1000.
λεπτὴ ἴς a small fibre of papyrus, Id. 17(1).795.