Yes, turn is playable
...and is worth 6 points.
Found in the following dictionaries
Enable (Words with friends)
SOWPODS (Collins Scrabble Words)
OTCWL2014 (NASPA Word List 2014)
TWL06 (NASPA List 2006)
"Turn" Definition
noun
A brief theatrical act or stage appearance.
A change of direction, motion, or position: Make a left turn at the corner.
A characteristic mood, style, or habit; a natural inclination: an inquisitive turn of mind.
A deed or action having a good or bad effect on another: "He thought some friend had done him an ill turn” ( Stephen Crane).
verb-transitive
Slang To perform (an act of prostitution): turning tricks.
To affect or change the color of: Autumn turns the green leaves golden.
To alter or control the functioning of (a mechanical device, for example) by the use of a rotating or similar movement: turned the iron to a hotter setting.
To blunt or dull (the edge of a cutting instrument).
To cause (a scale) to move up or down so as to register weight: Even a feather will turn a delicate scale.
verb-intransitive
To attack suddenly and violently with no apparent motive: The lion turned on the animal trainer.
To be formed on a lathe: a softwood that turns easily.
To be stocked and sold: This merchandise will turn easily.
To become dull or blunt by bending back. Used of the edge of a cutting instrument.
To change color: The leaves have turned.
phrasal-verb
Turn away To avert; deflect: turned away all criticism.
Turn away To repel: The poor location of the house turned away prospective buyers.
Turn away To send away; dismiss: turned away the clerk.
Turn back To drive back and away: turned back the uninvited comers.
Turn back To halt the advance of: turned back the advancing army.
verb
To cause to move around an axis or a center make rotate or revolve.
To cause to move around so as to effect a desired end (as of locking, opening, or shutting).
To affect or alter the functioning of (as a mechanical device) or the level of (as sound) by such movement.
To execute or perform by rotating or revolving.
To twist out of line or shape.