The word 硬化 (yìnghuà), meaning "to harden" or "harden," is formed through a common Chinese morphological process where the root character 硬 (yìng), meaning "hard" or "stiff," is combined with the verbalizing suffix 化 (huà), which denotes "to change into" or "to make." This structure follows a predictable pattern of "quality/state + 化" to create a verb indicating the process of acquiring that quality, effectively translating to "to make/become hard."