名詞 incidence:

1. the relative frequency of occurrence of something
   同義詞：relative incidence
2. the striking of a light beam on a surface

1. The incidence of cases of rape have increase over the last year.
   強(qiáng)奸案的發(fā)案率在去年有所增加。
2. The rate of incidence of a disease.
   發(fā)病率發(fā)生疾病的概率

in.ci.dence

n.（名詞）
The act or an instance of happening; occurrence:
發(fā)生，出現(xiàn)：發(fā)生的行為或事件；出現(xiàn)：
例句：
did not expect criticism and was surprised by its incidence.
受到未預(yù)料的批評而感到吃驚

Extent or frequency of occurrence:
發(fā)生頻率：出現(xiàn)的范圍、程度或頻率：
例句：
a high incidence of malaria in the tropics.
熱帶地區(qū)瘧疾的高發(fā)率

Physics
【物理學(xué)】
The arrival of radiation or a projectile at a surface.
入射：輻射或投影到某一表面
Angle of incidence.
入射角