把 (bǎ) is the marker of the "disposal construction" - one of the most important grammatical structures in Mandarin. A 把 sentence moves the object before the verb to emphasise what happens to it: 我关门 (I close the door) becomes 我把门关上 (I closed the door shut), emphasising the disposal or result affecting the object. The verb in a 把 sentence must carry a resultative or directional complement or some other element showing completion.

The character originally depicted a hand grasping a handle, and its literal meaning "handle, grip" is preserved in measure-word uses like 一把刀 (a knife, literally "one handle of knife") and 一把椅子 (a chair). This concrete meaning of grasping/handling underlies the abstract grammatical function of disposing of or doing something to an object.