石块 (shí kuài) literally combines 石 (shí), meaning 'stone' or 'rock', and 块 (kuài), a common measure word for solid, chunk-like objects. Together, it refers to a medium-sized, irregularly shaped piece of stone — larger than a pebble but smaller than a boulder. It emphasizes physical mass and solidity, often implying natural origin and rough texture.

This noun is frequently used in everyday contexts involving terrain, construction, or outdoor activities — for example, describing stones scattered on a path, used in garden landscaping, or found in riverbeds. Unlike the more technical term 岩石 (yánshí, 'rock') or the poetic 岩 (yán, 'cliff'), 石块 carries a neutral, concrete, and slightly informal tone. It appears commonly in descriptive writing, safety warnings (e.g., 'watch for loose stone chunks'), and children’s stories about nature or building.