丙烯 (bǐng xī) is the Chinese term for propylene, a colorless, flammable hydrocarbon gas with the chemical formula C₃H₆. It is widely used in industry to manufacture plastics—especially polypropylene—as well as synthetic rubber and other chemicals. The character 丙 (bǐng) is the third of the ten Heavenly Stems, historically used in naming and sequencing, but here it functions phonetically to indicate the 'bing' sound; 烯 (xī) is a semantic-phonetic compound meaning 'alkene', a class of unsaturated hydrocarbons containing at least one carbon–carbon double bond. Together, 丙烯 literally signals 'the alkene derived from propane', reflecting its structural relationship to propane (C₃H₈) minus two hydrogen atoms.

This word appears almost exclusively in scientific, technical, or industrial contexts—such as chemistry textbooks, safety data sheets, environmental reports, or factory documentation. It is rarely encountered in everyday conversation, and learners are unlikely to need it outside STEM-related studies or professional settings involving petrochemicals or materials science. Pronunciation must preserve the third tone on 丙 and first tone on 烯; mispronouncing either tone may cause confusion with unrelated words like 并 (bìng) or 晰 (xī).