Why is it tension in surface tension? Why is it called surface tension not surface compression?
 A: The primary reason is that surface tension arises from attractive interactions between the molecules of a liquid A. In the bulk there are other molecules of liquid A all around so the interactions are balanced. At the interface however, there is a lack of molecules A on one side which results in a net force that pulls the surface molecules in the direction of the bulk. Since this is a pulling action of the liquid itself arising from the attractive forces (not a pushing action of the other liquid) it is termed a tension.
A: Have a look at my answer to a related question. When using the du Noüy ring method for measuring surface tension the surface pulls on you rather than pushing. For more info have a look at the Wikipedia page describing methods for measuring surface tension. Note that the equipment is generically called a tensiometer because it works by measuring the pull the surface exerts.
As an analogy imagine holding a stretched rubber band. We say the rubber band is in tension because it exerts a pull on your hands not a push.
