مثنی

mus̤annā(pass. part. of ثنی 'to make two, to dualize,' etc., ii of ثنی 'to double,' etc.), part. adj. Doubled, double, two-fold, binary; dualized; dual, of the dualnumber; marked with two points, double-dotted (a letter):—s.m. A duplicate, a copy; the second; a counterpart; a junior or younger (as distinguished from the father of the same name);—(in Gram.) the dual number:—mus̤annābihi, vulg. mus̤annā-běh, s.m. 'That of which it is the copy,' the original of a copy.