display, storage
cooling, drying
bicycle, bike (informal), coat, luggage, magazine, plate, spice, toast, towel, vegetable, wine, etc.
roof
We mounted the canoe onto the car's roof rack.

hang sth on, put sth on, put sth onto, put sth in, put sth into, stack sth in, stack sth on, store sth in, store sth on
The wine is stored in special racks.

contain sth, hold sth
The racks along the wall held most of the costumes.

in a/the rack
He replaced the CD in the rack.

on a/the rack
Spread the flowers out to dry on a rack.

rack for
a rack for storing apples

rack of
racks of magazines

Rack is used with these nouns as the subject:
shudder, sob

Rack is used with these nouns as the object:
body, brain