noun /ˈkɒn.sɛpt/
a) An understanding retained in the mind, from experience, reasoning and/or 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).
b) In generic programming, a description of supported operations on a type, including their syntax and semantics.
Wikipedia foundation.