What is "to hitch up"

Hitch \Hitch\, v. t. [imp. & p. p. Hitched; p. pr. & vb. n. Hitching.]

1. To hook; to catch or fasten as by a hook or a knot; to make fast, unite, or yoke; as, to hitch a horse, or a halter; hitch your wagon to a star.

2. To move with hitches; as, he hitched his chair nearer. To hitch up.

   1. To fasten up.

   2. To pull or raise with a jerk; as, a sailor hitches up his trousers.

   3. To attach, as a horse, to a vehicle; as, hitch up the gray mare. [Colloq.]