We have the same problem with things being "in NP". It's clear that all of P is in NP, but not clear whether all of NP is in P. But people often say "NP" with the implication of "(apparently, as far as we know) not in P", which is not actually correct based on the meanings of those terms.

(In this case the problem is probably made worse by the mental interpretation of "NP" as "Not Polynomial", when it really means "Nondeterministic machine can solve in Polynomial time", and if a deterministic machine can solve something in polynomial time, a nondeterministic machine can do so as well!)