Blocking refers to the portion of a Fashion Show rehearsal where runs are choreographed. It involves deciding where models will be placed on the ramp for aesthetic and lighting purpos es.
Other /More definition:
Blocking refers to the procedure that creates the body and longevity in the finished hat. Blocking is to shape a hat using a Block. A Block is the wooden form use to establish the finished shape of felt hats
Moreover, Blocking is a term used to describe the action of molding a hat shape.