critical angle

critical-angle的词性：
n.（名词）

1. Physics The smallest angle of incidence at which a light ray passing from one medium to another less refractive medium can be totally reflected from the boundary between the two.
【物理学】 临界角：光线从一种媒质进入另一种折射率较小的媒质时，在两种媒质的界面发生全反射时的最小入射角

2. The angle of attack of an airfoil at which airflow abruptly changes, causing changes in the lift and drag of an aircraft.
临界迎角：气流发生突然变化致使飞机的升力和阻力发生变化时的机翼的迎角