The word "钢筋" is formed by combining the character "钢" (gāng), meaning "steel", with the character "筋" (jīn), meaning "tendon" or "sinew", resulting in a compound term that literally translates to "steel tendon". This directly denotes reinforced steel bars used in construction, where "钢" specifies the material and "筋" describes its function as a reinforcing element analogous to biological tendons.