Audio connectors/plug/jacks

Stereo plugs are TRS (Tip, Ring, Sleeve) connectors. The TRS indicate contact points where audio signals are passed on. There are just TS and TRRS connectors too.

Jack plug, in UK, refers to a female connector and an Jack socket to a make connector.

In US when a connector is fixed, its called a jack.

2.5mm (diameter) Male Stereo socket - not commonly used

3.5mm (diameter) Male Stereo socket - the most commonly used:

There is also a 6.3 mm which is also used but not as frequently as 3.5 mm.

An RCA (Radio Corporation of America - which found it ) Male socket