כסי, כָּסָה I (cmp. כסח) to make incisions, mark, count. Part. pass. כָּסוּי marked, distinguished. Pesik. R. s. 39 (ref. to Ps. LXXXI, 4, v. כֶּסֶא) מהו בכסא בחדש שהוא כ׳ (not כיסוי) what is bakkesé? In the month which is marked (v. infra).
    Nif. - נִכְסֶה,
    Nithpa. - נִתְכַּסֶּה to be marked, distinguished. Lev. R. s. 29 (ref. to Ps. l. c.) וכל החדשים אינן נִכְסִין אלא ליום חגנו are all other months (or New Moon Days) not marked?—But (it must be marked by) ‘a festive day’; [read:] חגו בפני עצמו והלא ניסן חדש נִכְסֶה ויש לו חג: (Ar. … חדש ונתכסה) but is not Nisan a marked month with a festival? (Answ.) Its festival is separate from it (not coinciding with the New Moon Day); אלא איזהו חדש נ׳ ויש לו חג וכ׳ but what month is there that is marked and has a festival, and that on the same day?; Pesik. Baḥod., p. 153ᵃ