( n. )
The change in the direction of ray of light, heat, or the like, when it enters obliquely a medium of a different density from that through which it has previously moved.
( n. )
The change in the direction of ray of light, heat, or the like, when it enters obliquely a medium of a different density from that through which it has previously moved.
Webster's Revised Unabridged English Dictionary. Пересмотренный полный словарь английского языка Webster. 2012