See the entire entry for ˀsr vb. to bind; to prohibit

TgO Gen37:7 :וְהָא אֲנַחנָא מְאַסְרִין אֵיסָרָן בְגוֹ חַקלָא : there we were, bundling sheaves in the middle of the field

See the entire entry for ˀsrh n.f. bundle