σῆψις · sēpsis — LSJ
fermentation, putrefaction, decay
fermentation, putrefaction, decay, αὐχμηραί τε νόσοι καὶ σήψιες Emp. 121; ὑγρῶν σάψιες Ti.Locr. 102c, cf. Arist. HA 569a28; τὸ τέλος τῆς κατὰ φύσιν φθορᾶς σ. ἐστιν Id. Mete. 379a8; σ. χλωρή Hp. Prorrh. 1.99; σ. ὀστέων,= σφάκελος, Moer. p.342P.
II the process by which the intestines reject that part of food which is not nutritious
(σήπω) the process by which the intestines reject that part of food which is not nutritious, opp. πέψις, Arist. GA 762a14, cf. Ath. 7.276d, and v. σήπω II.4. (Acc. to Gal. 19.373 Empedocles said that πέψις took place σήψει.)