The primary headword sfagidion, grammatically the diminutive form of the secondary one sfagi/s, is found only here. For related vocabulary see sigma 1702, sigma 1703, sigma 1704.
LSJ s.v. defines sfagi/s as a sacrificial knife, which is true of the four instances cited there: Euripides, Electra 811, 1142; Dionysius of Halicarnassus, Roman Antiquities 7.72; Polyaenus 3.9.40. Elsewhere, though, it sometimes means (as glossed here) a cook's or butcher’s knife: see e.g. Dionysius of Halicarnassus, Roman Antiquities 11.37.6 and 11.40.1 (th\n mageirikh\n sfragi/da); Michael Psellus, Chronographia 4.49 (mageirikh=| sfragi/di). Thus a sfagi/s may be used for a variety of purposes and its specific meaning depends on context -- much like the Suda's glossing word ma/xaira: see e.g. kappa 318, mu 302, pi 181, pi 3121, tau 1197, tau 1198. On the use of both terms to refer to sacrificial implements, see ThesCRA, v.5, 308-312.