Anticipation

One of the links mentioned that an action occurs in three parts: 1) the preparation for the action (this is anticipation) 2) the action 3) the termination of the action. In other words, anticipation prepares the audience for something that is going to take place.  Some examples for this principle is getting ready to arm you swing your arms back, raising your foot before you kick the ball, or staring at something before you pick it up.

Reference Links:

http://tysonanimationvisualarts.blogspot.com/2012/01/12-principles-of-animation-detailed.html

http://minyos.its.rmit.edu.au/aim/a_notes/anim_principles.html

http://www.siggraph.org/education/materials/HyperGraph/animation/character_animation/principles/anticipation.htm