Dictionary

noun

Definitions

1. An abstract entity used to describe quantity.

   Example: Zero, one, −1, 2.5, and pi are all numbers.

2. A numeral: a symbol for a non-negative integer.

   Example: The number 8 is usually made with a single stroke.

3. An element of one of several sets: natural numbers, integers, rational numbers, real numbers, complex numbers, and sometimes extensions such as hypercomplex numbers, etc.

   Example: The equation e^{i\pi}+1=0 includes the most important numbers: 1, 0, \pi, i, and e.

4. (Followed by a numeral; used attributively) Indicating the position of something in a list or sequence. Abbreviations: No or No., no or no. (in each case, sometimes written with a superscript "o", like Nº or №). The symbol "#" is also used in this manner.

   Example: Horse number 5 won the race.