When light or other waves pass from one medium to another at an oblique angle, the light slows down and changes direction.
NOTE: An oblique angle is one that is more or less than 90°.
To remember that refraction means change of direction, use the following mnemonic:
He made reference to wanting more action (refraction) and so there was a change in direction from all of them.
This will help you remember
REFRACTION = CHANGE IN DIRECTION