Rebar, or steel reinforcing bar, is a crucial construction material used to strengthen concrete structures like buildings, bridges, and roads. The word 钢筋 literally combines 钢 (gāng), meaning 'steel', and 筋 (jīn), meaning 'tendon' or 'sinew' — evoking the idea of a strong, load-bearing 'skeletal element' embedded in concrete, much like tendons support the human body.

This term is exclusively technical and appears almost entirely in civil engineering, architecture, and construction contexts. It is not used metaphorically or in everyday casual speech. In China, rebar quality, grade (e.g., HRB400), and proper installation are strictly regulated for safety. You’ll commonly see it on building sites, in construction specifications, or in discussions about infrastructure durability and earthquake resistance.