10 (ten) is the even natural number following 9 and preceding 11. Ten is the base of the decimal numeral system, the most common system of denoting numbers in both spoken and written language.

Linguistics

Mathematics

Ten is the smallest noncototient number. There are exactly 10 small Pisot numbers that do not exceed the golden ratio.

Decagon

A ten sided polygon is called a decagon.

Science

The SI prefix for 10 is "deca-". The meaning "10" is part of the following terms: 10 is: The metric system is based on the number 10, so converting units is done by adding or removing zeros (e.g. 1 centimetre = 10 millimetres, 1 decimetre = 10 centimetres, 1 meter = 100 centimetres, 1 dekametre = 10 meters, 1 kilometre = 1,000 meters).

Music

Religion

Abrahamic religions

The Ten Commandments in the Hebrew Bible are ethical commandments decreed by God (to Moses) for the people of Israel to follow.

Mysticism