'Yèyán' (shale) is a fine-grained sedimentary rock that forms in thin, parallel layers — much like the pages of a book, which is why the first character 页 (yè) means 'page' or 'leaf'. The second character 岩 (yán) means 'rock' or 'cliff', indicating its geological nature. Together, 页岩 literally conveys 'page-rock', vividly capturing its defining physical property: easy cleavage into thin sheets.

This term is used primarily in geology, earth science education, and energy discussions — especially regarding shale gas extraction. It appears in textbooks, field guides, and environmental reports. While not part of everyday conversation, learners may encounter it in academic contexts, news about natural resources, or museum exhibits on rock formation. Unlike common nouns such as 石头 (shítou, 'stone'), 页岩 is technical and precise, referring specifically to laminated, clay-rich sedimentary rock formed under low-grade metamorphic conditions.