hypothesis
     n 1: a proposal intended to explain certain facts or observations
     2: a tentative theory about the natural world; a concept that
        is not yet verified but that if true would explain certain
        facts or phenomena; "a scientific hypothesis that survives
        experimental testing becomes a scientific theory"; "he
        proposed a fresh theory of alkalis that later was accepted
        in chemical practices" [syn: {possibility}, {theory}]
     3: a message expressing an opinion based on incomplete evidence
        [syn: {guess}, {conjecture}, {supposition}, {surmise}, {surmisal},
         {speculation}]
     [also: {hypotheses} (pl)]
Source: WordNet® 2.0