Definitions (from a google search). Hope these help:
Theory: a well-substantiated explanation of some aspect of the natural world; an organized system of accepted knowledge that applies in a variety of circumstances to explain a specific set of phenomena; "theories can incorporate facts and laws and tested hypotheses"; "true in fact and theory"
Hypothesis: 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"
Law: a generalization that describes recurring facts or events in nature; "the laws of thermodynamics"
Assumption: premise: a statement that is assumed to be true and from which a conclusion can be drawn; "on the assumption that he has been injured we can infer that he will not to play"
Observation: any information collected with the senses
Data: factual information, especially information organized for analysis or used to reason or make decisions
Fact: when an observation is confirmed repeatedly and by many independent and competent observers, it can become a fact
Belief: any cognitive content (perception) held as true; religious faith
Dogma: a religious doctrine that is proclaimed as true without proof
Impression: a vague idea in which some confidence is placed; "his impression of her was favorable"; "what are your feelings about the crisis?"; "it strengthened my belief in his sincerity"; "I had a feeling that she was lying"
These are going into the archive's glossary section.