In general, to exert force, physical or moral, upon, either in urging to action or in restraining from it; press; urge; drive; restrain.Hence To urge with irresistible power, or with a force sufficient to produce the effect; compel; necessitate; oblige.To confine or hold by force; restrain from escape or action; repress or compress; bind.To check; repress; hinder; deter.To force.In mech.: To prevent the occurrence of (motion), except in a particular direction: as, the relative motions of the parts of any machine are always constrained.To prevent the operation of the motion of (a material point or body), except in a particular and definite manner: as, to constrain a part of a mechanism.