The word 支撑 is formed by combining two characters that each contribute a related action to create a unified concept. The first character, 支, originally depicted a hand holding a branch, conveying the core idea of propping or supporting something. The second character, 撑, is more forceful and vivid, composed of a hand radical acting upon the component for "palm", intensifying the notion of pushing upward or bearing a load. Together, they visually and semantically merge into a single verb meaning to hold up from below, to sustain, or to support, with the second character reinforcing and specifying the active, physical nature of the support implied by the first.