To break down. (a) To crush; to overwhelm; as, to break down one's strength; to break down opposition. (b) To remove, or open a way through, by breaking; as, to break down a door or wall. -- To break in. (a) To force in; as, to break in a door. (b) To train; to discipline; as, a horse well broken in. -- To break of, to rid of; to cause to abandon; as, to break one of a habit. -- To break off. (a) To separate by breaking; as, to break off a twig. (b) To stop suddenly; to abandon. "Break off thy sins by righteousness." Dan. iv. 27. -- To break open, to open by breaking. "Open the door, or I will break it open." Shak. -- To break out, to take or force out by breaking; as, to break out a pane of glass. -- To break out a cargo, to unstow a cargo, so as to unload it easily. -- To break through. (a) To make an opening through, as, as by violence or the force of gravity; to pass violently through; as, to break through the enemy's lines; to break through the ice. (b) To disregard; as, to break through the ceremony. -- To break up. (a) To separate into parts; to plow (new or fallow ground). "Break up this capon." Shak. "Break up your fallow ground." Jer. iv. 3. (b) To dissolve; to put an end to. "Break up the court." Shak. -- To break (one) all up, to unsettle or disconcert completely; to upset. [Colloq.]