specialist

From WikiWord, the free dictionary

/ˈspɛʃəlɪst/ English

Definitions

Someone who is an expert in, or devoted to, some specific branch of study or research.
A physician whose practice is limited to a particular branch of medicine or surgery.
Any of several non-commissioned ranks corresponding to that of corporal.
An organism that is specialized for a particular environment.“The tree Lepidothamnus laxifolius is a high alpine specialist found in high-altitude bog communities and in scrub.”