An abstract and general idea; an abstraction.
A description of supported operations on a type, including their syntax and semantics.
Understanding retained in the mind, from experience, reasoning and imagination; a generalization (generic, basic form), or abstraction (mental impression), of a particular set of instances or occurrences (specific, though different, recorded manifestations of the concept).
to conceive; to dream up
A recurring theme.
A melodic theme associated with a particular character, place, thing or idea in an opera.