Question

what did you mean by surface tension

Answer 1

Surface tension is a property of liquid through which liquid tries to attained minimum area of given volume of liquid.

Answer 2

The liquid molecules which are below the surface are in equilibrium.  The liquid molecules which are at the surface are attracted by other molecules in downward direction. So, a force is originated to balance the surface molecules which is equal but opposite in direction to the downward force. This force is called surface tension.