Conjugate mirrors

(Optics) two mirrors so placed that rays from the focus of one are received at the focus of the other, especially two concave mirrors so placed that rays proceeding from the principal focus of one and reflected in a parallel beam are received upon the other and brought to the principal focus.

See also: Conjugate

Webster's Revised Unabridged Dictionary, published 1913 by G. & C. Merriam Co.