(n.) The degree to which a lens, mirror, or any optical instrument, magnifies; in the telescope, and usually in the microscope, the number of times it multiplies, or augments, the apparent diameter of an object; sometimes, in microscopes, the number of times it multiplies the apparent surface.
POWER (15)
Meaning of POWER (15) in English
Webster's English dictionary. Английский словарь Webster. 2012