What does counter clockwise means in math term?

Answer 1

Counter clockwise means that a curve has "positive orientation". You are traveling in a counter clockwise direction if the "interior" of the curve is on the left of the direction you are traveling.

You are traveling in a clockwise direction if the "interior" is located on the right.

This notion of direction is important when doing certain advanced calculations, such as line integrals - evaluating in the wrong direction will possibly give you a negative answer!