Clockwise and Counterclockwise
Clockwise means moving in the direction of the hands on a clock.
Try it yourself:
Faucets (taps) get closed, and most screws and bolts get tightened by turning clockwise.
Counterclockwise / Anticlockwise
The opposite direction is called counterclockwise in the US (or anticlockwise in the UK).
Angles from a line are measured counterclockwise (and a negative angle goes clockwise):
BUT compass bearings are measured clockwise:
So Which Way?
Clock hands go clockwise, taps are closed clockwise, screws are tightened clockwise, compass bearings go clockwise.
But angles are measured counterclockwise.
Such long words deserve to be shortened.
So clockwise can be shortened to CW.
And counterclockwise to CCW (or maybe ACW for anticlockwise).