Typically a tuner, preamp and power amplifier combined into one unit. Sometimes called a receiver. If it includes video inputs and/or surround sound decoders, it is also referred to a Home Theater receiver.
Sometimes called a control amplifier, this is a receiver minus a tuner or, if you like, a power amplifier plus a preamplifier. Some integrated amplifiers are very elaborate and contain A/V switching and even surround-sound processing.
An integrated amplifier is an electronic device containing an audio preamplifier and amplifier in one unit, as opposed to separating the two. Most modern audio amplifiers are integrated and have several inputs for devices such as CD players, DVD players, and auxiliary sources. Integrated amplifiers commonly had dedicated inputs for turntables, AM/FM tuner, and tape recorders (cassette or reel-to-reel) back when those devices were more common.