危 is used in: 危险 (dangerous), 危机 (crisis), 危害 (to harm), 危急 (critical/urgent), 濒危 (endangered). It is almost always used in compounds.
culture
The Chinese word for crisis, 危机 (wēijī), combines 危 (danger) and 机 (opportunity). While the popular claim that 'crisis = danger + opportunity' is an oversimplification, the pairing reflects a Chinese philosophical perspective on challenges.
