Turn/tɜːrn/ Definition 1 of 5Pro Tip 1/3Physical Action Use 'turn' when talking about moving something to a different position. She turned the dial until the safe opened. Pro Tip 2/3Starting Devices When starting machines or devices, 'turn' is often used. Can you turn on the TV? Pro Tip 3/3Degree of Rotation Specify how much to turn something, like 'half turn' or 'full turn'. Give the bolt a quarter turn to tighten it.