n. The concentration of one's efforts upon a particular field of study
the GNU version of the Collaborative International Dictionary of English
n. Devotion to a particular and restricted part or branch of knowledge, art, or science.
The Century Dictionary and Cyclopedia
n. Devotion to a special branch or division of a general subject or pursuit; the characteristic pursuit or theme of a specialist; restriction to a specialty.
WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
n. the special line of work you have adopted as your career
n. the concentration of your efforts on a particular field of study or occupation
Word Usage
"The loss of monopolies of knowledge and specialism is recorded in many fun books, like Parkinson's Law and The Peter Principle and One-up-man-ship."