Short Track

A short track is an oval less than 1 mile in length.

Intermediate Track

An intermediate track is an oval equal to or greater than 1 mile but less than 2 miles.

SuperSpeeedway

Technically a superspeedway is an oval which is equal to or greater than 2 miles in length.
NASCAR only categorizes Daytona International Speedway and Talladega Superspeedway
as superspeedways. Additionally, they are the only tracks where restrictor plates are used.

Road Course

A road course is a racing circuit comprised of both left-hand and right-hand
turns, as opposed to an oval which is comprised exclusively of left-hand turns.

FYI: All NASCAR track lengths are measured 15 feet from the outside wall.