What is "to turn on"

Turn \Turn\, v. i.

1. To move round; to have a circular motion; to revolve entirely, repeatedly, or partially; to change position, so as to face differently; to whirl or wheel round; as, a wheel turns on its axis; a spindle turns on a pivot; a man turns on his heel.

   The gate . . . on golden hinges turning.
   --Milton.

2. Hence, to revolve as if upon a point of support; to hinge; to depend; as, the decision turns on a single fact.

   Conditions of peace certainly turn upon events of war.
   --Swift.

3. To result or terminate; to come about; to eventuate; to issue.

   If we repent seriously, submit contentedly, and serve him faithfully, afflictions shall turn to our advantage.
   --Wake.

4. To be deflected; to take a different direction or tendency; to be directed otherwise; to be differently applied; to be transferred; as, to turn from the road. Turn from thy fierce wrath. --Ex. xxxii. 12. Turn ye, turn ye from your evil ways. --Ezek. xxxiii. 1

   1. The understanding turns inward on itself, and reflects on its own operations.
      --Locke.

5. To be changed, altered, or transformed; to become transmuted; also, to become by a change or changes; to grow; as, wood turns to stone; water turns to ice; one color turns to another; to turn Mohammedan.

   I hope you have no intent to turn husband.
   --Shak.

   Cygnets from gray turn white.
   --Bacon.

6. To undergo the process of turning on a lathe; as, ivory turns well.

7. Specifically:

   1. To become acid; to sour; -- said of milk, ale, etc.

   2. To become giddy; -- said of the head or brain.

      I'll look no more; Lest my brain turn.
      --Shak.

   3. To be nauseated; -- said of the stomach.

   4. To become inclined in the other direction; -- said of scales.

   5. To change from ebb to flow, or from flow to ebb; -- said of the tide.

   6. (Obstetrics) To bring down the feet of a child in the womb, in order to facilitate delivery.

8. (Print.) To invert a type of the same thickness, as temporary substitute for any sort which is exhausted. To turn about, to face to another quarter; to turn around. To turn again, to come back after going; to return. --Shak. To turn against, to become unfriendly or hostile to. To turn aside or To turn away.

   1. To turn from the direct course; to withdraw from a company; to deviate.

   2. To depart; to remove.

   3. To avert one's face. To turn back, to turn so as to go in an opposite direction; to retrace one's steps. To turn in.

      1. To bend inward.

      2. To enter for lodgings or entertainment.

      3. To go to bed. [Colloq.] To turn into, to enter by making a turn; as, to turn into a side street. To turn off, to be diverted; to deviate from a course; as, the road turns off to the left. To turn on or To turn upon.

         1. To turn against; to confront in hostility or anger.

         2. To reply to or retort.

         3. To depend on; as, the result turns on one condition. To turn out.

            1. To move from its place, as a bone.

            2. To bend or point outward; as, his toes turn out.

            3. To rise from bed. [Colloq.]

   4. To come abroad; to appear; as, not many turned out to the fire.

   5. To prove in the result; to issue; to result; as, the crops turned out poorly. To turn over, to turn from side to side; to roll; to tumble. To turn round.

      1. To change position so as to face in another direction.

      2. To change one's opinion; to change from one view or party to another. To turn to, to apply one's self to; have recourse to; to refer to. ``Helvicus's tables may be turned to on all occasions.'' --Locke. To turn to account, profit, advantage, or the like, to be made profitable or advantageous; to become worth the while. To turn under, to bend, or be folded, downward or under. To turn up.

         1. To bend, or be doubled, upward.

         2. To appear; to come to light; to transpire; to occur; to happen.