The number 10. It comes after nine. Ten is the base of our decimal number system.

Ordinal: tenth. Common collocations: ten out of ten (a perfect score), ten-minute break, ten o'clock. The prefix 'deci-' means ten (decimal, decade = ten years, December was originally the tenth month).

10 Downing Street is the official home and office of the British Prime Minister. 'A perfect ten' means someone or something is absolutely perfect. Counting 'ten to one' is used to build anticipation. The Ten Commandments are central to Christian and Jewish traditions.