How is the meaning of theory in science different from the everyday use of the term?

Question

aaronq · Answer

Most people interpret theory as "a guess", but "A scientific theory is a well-substantiated explanation of some aspect of the natural world, based on knowledge that has been repeatedly confirmed through observation and experimentation..." http://en.wikipedia.org/wiki/Scientific_theory

anonymous · Answer

evidence shows that hippos and whales are closely related organisms. how might evolution and adaptation account for similar and differences between them???