Turn

1. To cause to move around an axis or a center; cause to rotate or revolve. Turn up the heat in the oven.
2. To cause to move around in order to achieve a result, such as opening, closing, tightening, or loosening. Turn the key to start the car.
3. To change the position of disposition of by folding. bending, or twisting. You need to turn the hat inside out.
4. To injure by twisting. The fall turned her ankle.
5. To change the direction or course of. He turned the car to the left.
6. To devote or apply (oneself, for example) to something. She turned her efforts to music.
7. To get by buying and selling. The business turned a fair profit.
8. To perform an act of prostitution. She earned her living by turning tricks.
9. To become sour. The milk turned in the heat.
10. A point marking the end of one period of time and the beginning of the next. At the turn of the century we all hoped for better times.