What is Four ?
Four is (noun) 1. the number 4 A square has four corners. He’s four (years old). I have an appointment with the doctor at four (o’clock). on all fours on hands and knees He was creeping around under the desk on all fours. 2. a crew of four rowers in a boat Our college four won the race. 3. (in cricket.) a score of four runs for sending the ball over the boundary He scored a century, including seven fours and two sixes.
source: Easier English, Student Dictionary Upper Intermediate Level