incidence
🇺🇸
/ˈɪnsɪdəns/
🇬🇧
/ˈɪnsɪdəns/
how often something happens
The incidence of flu is higher in winter months.
流感的发病率在冬季月份更高。
how light hits a surface
The incidence of light on the mirror creates a reflection.
光线在镜子上的入射会产生反射。