virtual [via the technical term `virtual memory', prob. from the term `virtual image' in optics] adj. 1. Common alternative to logical; often used to refer to the artificial objects (like addressable virtual memory larger than physical memory) created by a computer system to help the system control access to shared resources. 2. Simulated; performing the functions of something that isn't really there. An imaginative child's doll may be a virtual playmate. Oppose real.