to pursue some special line of study, work, etc.; have a specialty

The doctor specializes in gastroenterology.

Biology . (of an organism or one of its organs) to be adapted to a special function or environment.

to render special or specific; invest with a special character, function, etc.

to adapt to special conditions; restrict to specific limits.

to restrict payment of (a negotiable instrument) by endorsing over to a specific payee.

to specify; particularize.

verb

broaden

verb

be into , develop oneself in , do one’s thing , go in for , have a weakness for , limit oneself to , practice , practice exclusively , pursue , study intensively , train , work in , concentrate , major