a transparent optical device used to converge or diverge transmitted light and to form images | the lens or system of lenses in a telescope or microscope that is nearest the object being viewed |
electronic equipment that uses a magnetic or electric field in order to focus a beam of electrons | the goal intended to be attained (and which is believed to be attainable) |
biconvex transparent body situated behind the iris in the eye; its role (along with the cornea) is to focus light on the retina | |
(metaphor) a channel through which something can be seen or understood | |