Jastrow: עִיסּוּרְיָתָא

עִיסּוּרְיָתָא, עִיסֻּרְ׳, עִישּׂוֹרְ׳ f. pl. (עֲסַר) 1) divisions of ten. Targ. O. Deut. I, 15; Ex. XVIII, 21 ed. Berl. (oth. ed. a. Y. עִישּׂוֹ׳). —2) arrangement of tenth portions in succession. Ned. 39ᵇ כעיש׳ דבי רבי like the arrangement in the house of Rabbi (that the first daughter gets one-tenth of the estate, the second one-tenth of the remainder and so on). —3) (of coins) decades, groups of tens. B. Mets. 64ᵃ top בע׳ וחומשייתא (a reasonable mistake is) a mistake in decades or in fives (where you count by tens or fives).