Displacement

ONE :

• the act or process of displacing : the state of being displaced a storm that caused the displacement of thousands of people.

TWO :

• a) physics : the volume or weight of a fluid (such as water) displaced (see displace sense 2a) by a floating body (such as a ship) of equal weight.
• b) : the difference between the initial position of something (such as a body or geometric figure) and any later position
• c) mechanical engineering : the volume displaced by a piston (as in a pump or an engine) in a single stroke

also, automotive vehicles : the total volume so displaced by all the pistons in an internal combustion engine

THREE (psychology):

• a : the redirection of an emotion or impulse from its original object (such as an idea or person) to another, the displacement of his emotions
• b : the substitution of another form of behaviour for what is usual or expected especially when the usual response is nonadaptive or socially inappropriate

called also displacement activity, displacement behaviour