The American Heritage® Dictionary of the English Language, 4th Edition
n. One who is devoted to a particular occupation or branch of study or research: "Specialists . . . tend to think in grooves” ( Elaine Morgan).
n. A physician whose practice is limited to a particular branch of medicine or surgery, especially one who is certified by a board of physicians: a specialist in oncology.
n. Any of several noncommissioned ranks in the U.S. Army that correspond to that of corporal through sergeant first class.
n. Someone who is an expert in, or devoted to, some specific branch of study or research.
n. A physician whose practice is limited to a particular branch of medicine or surgery.
n. Any of several non-commissioned ranks corresponding to that of corporal.
the GNU version of the Collaborative International Dictionary of English
n. One who devotes himself to some specialty
The Century Dictionary and Cyclopedia
n. A person who devotes himself to a particular branch of a profession, science, or art; one who has a special knowledge of some particular subject: thus, ophthalmologists, neurologists, or gynecologists are specialists in medicine.
WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
n. an expert who is devoted to one occupation or branch of learning
n. practices one branch of medicine
Word Usage
"In the case of NetizensForBradley. org, the specialist is the young Greg Laynor, who has read all the FEC literature but still concludes that "it's not clear if we're doing something wrong.""