ثلث

الثَّلَاثَاآءُ الثلاثاآء , also written الثَّلٰثَاآءُ, (Lth, T, S, M,) or يَوْمُ الثَّلَاثَاآءِ or الثَّلٰثَاآءِ, (A, Msb, K,) and ↓ الثُّلَاثَاآء, with damm, (A, K,) [meaning The third day of the week, Tuesday, ] has this form for the sake of distinction; for properly it should be الثَّالِثُ: (S, M:) or it has meddeh in the place of the ة in the noun of number [ثَلَاثَةٌ] to distinguish it from the latter: (Lth, T:) [it is without tenween in every case; when indeterminate as well as when determinate; being fem.:] the pl. is ثَلَاثَاوَاتٌ (S, M, Msb) and أَثَالِثُ. (Th, M.) It has no dim. (Sb, S in art. امس.) Lh relates that Aboo-Ziyád used to say, مَضَى الثَّلَاثَاآءُ بِمَا فِيهِ [ Tuesday passed with what occurred in it ]; making ثلاثاء sing. and masc.; [but this he did because he meant thereby يَوْمُ الثَّلَاثَاآءِ; يوم being masc.:] Th is related to have said, بِمَا فِيهَا; making it fem.: and Abu-l-Jarráh used to say, مَضَتِ الثَّلَاثَاآءُ بِمَا فِيهِنَّ, treating the word as a numeral. (M.)