definition of
supposition

[1] #1 supposition n. [guess, conjecture, surmise, surmisal, speculation, hypothesis] a message expressing an opinion based on incomplete evidence. wn

[2] #2 supposition n. [assumption, supposal] a hypothesis that is taken for granted; "any society is built upon certain assumptions". wn

[3] #3 supposition n. [supposal] the cognitive process of supposing. wn