Originally Posted by Merriam Webster

hypothesis
Pronunciation:
\hī-ˈpä-thə-səs\
Function:
noun
Inflected Form(s):
plural hypotheses
Etymology:
Greek, from hypotithenai to put under, suppose, from hypo- + tithenai to put — more at do
Date:
circa 1656

1 a: an assumption or concession made for the sake of argument b: an interpretation of a practical situation or condition taken as the ground for action
2: a tentative assumption made in order to draw out and test its logical or empirical consequences
3: the antecedent clause of a conditional statement