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Webster 1913 Edition

Noun.

[L.

aemulator

One who emulates, or strives to equal or surpass.

As Virgil rivaled Homer, Milton was the

emulator

of both.

Bp. Warburton.

, ,

Noun.

One who emulates; a rival; a competitor.

See also: emulátor

emulator ‎(plural emulators)

A person or thing that emulates.
...but I find in the life of this emulator of Caesar actions which, if necessity warranted, the heart must still refuse to approve...
(computing) A piece of software or hardware that simulates another system.

device that acts as something else

software or hardware application that simulates another system