adj. 1 that is such for practical purposes though not in name or according to strict definition (is the virtual manager of the business; take this as a virtual promise). 2 Optics relating to the points at which rays would meet if produced backwards (virtual focus; virtual image). 3 Mech. relating to an infinitesimal displacement of a point in a system. 4 Computing not physically existing as such but made by software to appear to do so (virtual memory). virtuality n. virtually adv.
[ ME f. med.L virtualis f. L virtus after LL virtuosus ]