SUPPOSAL Meaning of SUPPOSAL in English /seuh poh"zeuhl/ , n.1. the act of supposing. 2. something that is supposed; conjecture or notion. [ 1350-1400; ME supposaille. See SUPPOSE, -AL 2 ] Random House Webster's Unabridged English dictionary. Полный английский словарь Вебстер - Random House . 2012