Theory
Part of speech: noun
Definition: An unproven conjecture. An expectation of what should happen, barring unforeseen circumstances. A coherent statement or set of statements that attempts to explain observed phenomena. A logical structure that enables one to deduce the possible results of every experiment that falls within its purview. A field of study attempting to exhaustively describe a particular class of constructs. A set of axioms together with all statements derivable from them.
Example sentence: A young man is a theory, an old man is a fact.
Hypothesis
Part of speech: noun
Definition: A tentative conjecture explaining an observation, phenomenon or scientific problem that can be tested by further observation, investigation and/or experimentation.(general) An assumption taken to be true for the purpose of argument or investigation.The antecedent of a conditional statement.
Example sentence: The word 'belief' is a difficult thing for me. I don't believe. I must have a reason for a certain hypothesis. Either I know a thing, and then I know it - I don't need to believe it.