臂

The primary meaning is the upper limb. Metaphorically, it refers to an essential aide or primary instrument of power, as well as the reach and extent of one's influence.

Functions almost exclusively as a noun, serving as a concrete subject or object. It is frequently modified by adjectives describing length, strength, or color.

In early texts, there is fluid overlap between 臂 and 手 (//shǒu//). While //shǒu// often serves as a general term for the entire upper extremity and typically denotes agency or grasping, 臂 narrows the focus to the limb's structure, denoting length, strength, or reach.