Ologist

Part of speech: noun

Definitions

1. A professional who studies, specializes in, or practices a specific branch of knowledge or science
2. an expert within the domain of a designated field
3. A practitioner or scholar dedicated to understanding and researching a particular scientific or academic discipline

Etymology: The "-ologist" in this word is a suffix, and it is a two-step building block. The Greek "-logos" meant something like "word", "speech" or "reasoning", and it gave English the "-logy" ending found in words like "biology" and "geology", where it names a field of study. Adding "-ist" turns that field into the person who practises it, so an "-ologist" is someone who works in a given "-ology". The suffix was put to heavy use in the 1800s, when scientists were naming new disciplines faster than ever and needed a tidy pattern for them. Each new "-ology" produced its matching "-ologist" almost automatically, which is why the ending now appears in so many professional titles. Anyone can, in principle, coin a fresh one: a researcher who studies a niche subject can simply attach the suffix to a new root and be understood at once.