1. To perform a work or labour; to exert power or strengh, physical or mechanical; to act.

2. <medicine> To produce an appropriate physical effect; to issue in the result designed by nature; especially, to take appropriate effect on the human system.

3. To act or produce effect on the mind; to exert moral power or influence. "The virtues of private persons operate but on a few." (Atterbury) "A plain, convincing reason operates on the mind both of a learned and ignorant hearer as long as they live." (Swift)

4. <surgery> To perform some manual act upon a human body in a methodical manner, and usually with instruments, with a view to restore soundness or health, as in amputation, lithotomy, etc.

5. To deal in stocks or any commodity with a view to speculative profits.

Origin: L. Operatus, p.p. Of operari to work, fr. Opus, operis, work, labour; akin to Skr. Apas, and also to G. Uben to exercise, OHG. Uoben, Icel. Fa. Cf. Inure, Manoeuvre, Ure.

(01 Mar 1998)