Pronunciation: (vûr'chOO-ul),[key] —adj. 1. being such in power, force, or effect, though not actually or expressly such: a virtual dependence on charity. 2. Optics. a. noting an image formed by the apparent convergence of rays geometrically, but not actually, prolonged, as the image formed by a mirror (opposed to real).
b. noting a focus of a system forming virtual images.
3. temporarily simulated or extended by computer software: a virtual disk in RAM; virtual memory on a hard disk.