Meaning of “turn” - Learner’s Dictionary

turn

verb uk us /tɜːn/
MOVE YOUR BODY [ I ]

B1 to move your body so that you are facing a different direction:

Ricky turned and saw Sue standing in the doorway.
CHANGE DIRECTION [ I, T ]

A2 to change direction when you are moving, or to make a car do this:

Turn left at the traffic lights.
I turned the car into the drive.
CHANGE POSITION [ T ]

to move something round so that it faces a different direction:

Ella turned the cup to hide the crack in it.
GO ROUND [ I, T ]

B2 to move around a central point in a circle, or to make something do this:

Turn the steering wheel as quickly as you can.
turn blue/cold/sour, etc

B2 to become blue, cold, etc:

The sky turned black and it started to rain.
turn 16/21, etc

to become a particular age:

He turned 18 last May.

(Definition of “turn verb” from the Cambridge Learner’s Dictionary © Cambridge University Press)