נָכַס (cmp. כָּסַס) 1) to cut; to slaughter. Imper. כּוֹס. Pes. 61ᵃ (expl. תכסו, Ex. XII, 4) טלה זה לשון סורסי הוא … כוס לו it is an abbreviated form (v. סוּרְסִי), as one says to his neighbor, kos (for נְכוֹס) &c., cut this lamb for me; Y. ib. V, 32ᵃ bot.; Mekh. Bo. s. 3.—Snh. 82ᵇ (play on כזבי, Num. XXV, 15) שאמרה לאביה כוס בי עם זה she said to her father, cut (ruin) this people through me. Ḥull. 37ᵇ בְּשַׂר כוס כוס meat of an animal about which one says, ‘cut, cut’, i.e. meat of an animal hurriedly cut, because it threatens to die; Treat. Kuthim (ed. Kirchh., p. 33, sq.) we must not sell to Samaritans כּוֹסְכּוֹס (sub. בשר) meat of an animal on the point of death. —2) to mark, count, v. נְכָסִים.