Three (3) is the natural number following two and preceding four.

Three is the second smallest prime number, the next is five. Three is the second triangular number.

3 goes into 9 exactly 3 times, so fractions with 3 in the denominator have a single digit repeating sequences in their decimal expansions. A natural number is divisible by three if and only if its decimal digit sum is divisible by 3. The base-3 numeral system is the ternary system.

A polygon with three sides is a triangle.

Three is also the number of musicians in a trio.

Many human cultures have given the concept of three-ness symbolic meanings:

The Holy Trinity in Christian doctrine
The process of synthesis in Hegelian dialectic creates three-ness from two-ness
The three Doshas (weaknesses) and their antidotes are the basis of Ayurvedic medicine, for a complete system of medicine in India
The three Gunas underlie action, in the Vedic system of knowledge.
The Trimurti in Hindu tradition

Three (三 pinyin san1) is considered a good number in Chinese culture because it sounds like the word "alive" (生 pinyin sheng1), compare to four.

Decals and bumper stickers bearing the phrase "In Memory of 3" are references to NASCAR driver Dale Earnhardt.

Other uses for three:

Three's Company
Three of a Kind
Three: a rock band formed by Keith Emerson, Robert Berry and Carl Palmer
Three Kingdoms
Three Gorges
Three links
Three Principles of the People
Three Represents
Three Years of Natural Disasters
3 (band)

See also: one, two, three, four, five, integer, list of numbers.

This article is about the number. For the year AD 3, see 3.

Preceded by:
two

Integers

Succeeded by:
four