In communications and information theory, a receiver is the recipient(observer) of a message, which is sent from a source. Receivers decode messages.

In radio terminology, a receiver is a device that receives a radio signal from an antenna and converts it to useful information in the form of sound, pictures, navigational position information, etc. (The terms radio and radio receiver are often used specifically for receivers whose output consists only of sound, although other types of receiver, such as television receivers, are technically radio receivers as well.)

In consumer electronics, a receiver is a combination of a radio broadcast tuner and an amplifier for the speakers, as well as selection for sources (CD, tape, etc.) and adjustments for audio, such as a graphic equalizer or basic tone controls.

On a telephone, the "receiver" is the handset, particularly the earpiece.

In firearms terminology, the receiver is the part of the firearm that houses the operating parts of the gun. In most cases, it is made up of forged or stamped metal, and the moving parts reciprocate and cycle within it.

In strictly legal terms, the receiver is the actual firearm itself, and as such it is the controlled part (without which operating is impossible). Generally, the law views the receiver as that part of a firearm housing that has the serial number upon it. Thus, in the case that a firearm has multiple receivers, the legally controlled one is the one that is serialized.