A distinct type of kicking strike which is physically distinguishable by striking in a linear Line of Travel - making contact with the knife-edge of the foot.

Comments:

This kick does not necessarily refer to direction, but rather the point of contact of the foot (the side).

By definition, this kick either uses a Thrusting (or Snapping) Method of Execution.

From one perspective, this kick is the lower body equivalent to the hand-sword.

The word side, in this case, is equivalent to flank, but also equivalent to weapon contact point.

A.K.A.:

Knife Edge kick