Dining or dinner room? Could you help me?

Question

What's the difference between these?

I made a little description of what I understood but I don't know if they're right.

1) Horse racing: refers to an activity.

2) Horse race: refers to a race which is carried out by horses.

3) Horse's race: implies a race of one horse particularly.

and these...

1) Dining room or dinner room?

2) Is the computer an studying or study device?

3) My very neat home clothes or clothing area?

I think the meaning is almost the same!

Thanks in advance! Your help is really really appreciated.

Answer 1

1) Dining room or dinner room?

Dining room is a place where people eat.  Dinner room is a place where people eat dinner.

2) Is the computer an studying or study device?

A computer is a study device.  A computer is a device used for studying.

3) My very neat home clothes or clothing area?

Home clothes are clothese that you wear at home.  A clothing area is a place you either put your clothes or a place you take care of your clothes at.

Answer 2

You can eat at any time at a dining room but dinner room is only for dinner.