Also found in: Medical.
focal power[′fō·kəl ‚pau̇·ər]
A measure of the ability of a lens, mirror, prism, or optical system to converge a parallel beam of light; equals the reciprocal of the focal length. Also known as power.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.