virtual

American Heritage® Dictionary of the English Language, Fourth Edition

1. adj. Existing or resulting in essence or effect though not in actual fact, form, or name: the virtual extinction of the buffalo.
2. adj. Existing in the mind, especially as a product of the imagination. Used in literary criticism of a text.
3. adj. Computer Science Created, simulated, or carried on by means of a computer or computer network: virtual conversations in a chatroom.

Century Dictionary and Cyclopedia

1. In electricity, in alternating currents, effective: said of the value which is to be used in computing energy or power relations of a current.
2. In synchronous alternating-current machines, the induced electromotive force corresponding to the resultant of the magnetomotive forces of field-flux and armature-flux.
3. Existing in effect, power, or virtue, but not actually: opposed to real, actual, formal, immediate, literal.
4. Pertaining to a real force or virtue; potential.
5. In mech., as usually understood, possible and infinitesimal: but this meaning seems to have arisen from a misunderstanding of the original phrase virtual velocity, first used by John Bernoulli, January 26th, 1717, which was not clearly defined as a volocity at all, but rather as an infinitesimal displacement of the point of application of a force resolved in the direction of that force. The principle of virtual velocities is that, if a body is in equilibrium, the sum of all the forces each multiplied by the virtual velocity of its point of application is, for every possible infinitesimal displacement of the body, equal to zero. The epithet appears to have been derived from an older statement that when, by means of any machine, two weights are brought into equilibrium, the velocities are inversely as the weights; so that virtual would here mean practical, as in def. 1.

Wiktionary

1. adj. In effect or essence, if not in fact or reality; imitated, simulated.
2. adj. Nearly, almost. (A relatively recent corruption of meaning, attributed to misuse in advertising and media.)
3. adj. Of something that is simulated in a computer or on-line.
4. adj. computing, object-oriented programming In object-oriented programming, capable of being overridden with a different implementation in a subclass.
5. adj. Related to technology.
6. n. computing In C++, a virtual member function of a class.

GNU Webster's 1913

1. adj. Having the power of acting or of invisible efficacy without the agency of the material or sensible part; potential; energizing.
2. adj. Being in essence or effect, not in fact.

WordNet 3.0

1. adj. existing in essence or effect though not in actual fact
2. adj. being actually such in almost every respect