is it called frosted if glass looks sort of foggy?

Answer 1

yep

Answer 2

Yes, the classic way to achieve it is to etch the glass by sand blasting it. (Since the result is an irregular surface, it shouldn't be one exposed to uses that get wet as the tiny fissures will harbor bacteria. So it goes on the outside of drinking glasses and shower doors, etc.)
Glass can also look foggy from the accumulation of minerals in hard water. Vinegar will melt away the residue.