a box that interfaces with your PC and emulates the operation of your target processor

a debug tool with two functional groups of features

a sophisticated device that pretends that it is the microprocessor itself, while at the same time capturing information

Short for In-Circuit Emulator (ICE). A debugging tool that takes the place of (emulates) the processor on your target board. Emulators frequently incorporate a special "bond-out" version of the target processor that allows you to observe and record its internal state as your program is executing.

See in-circuit emulator. Any debugging tool that pretends to be a system resource and adds additional functionality or remote visibility. See also ROM emulator.