Merriam-Webster Collegiate Dictionary - subspecies

 noun  Etymology: New Latin  Date: 1699 a subdivision of a species: as  a. a category in biological classification that ranks immediately below a species and designates a population of a particular geographic region genetically distinguishable from other such populations of the same species and capable of interbreeding successfully with them where its range overlaps theirs  b. a named subdivision (as a race or variety) of a taxonomic species  c. subgroup 1 a political ~  • subspecific adjective