What is Number?

Number:
What is:
idea, abstract concept, abstract entity, mathematical object, ...

What it does:
Count, Measure, describe, label, order, ...

• Quantity of Objects

• An arithmetical value expressed by a word, symbol or figure
representing a particular quantity used in counting or making
calculation

• A mathematical object used to count, measure and label

Number:

A number is a count or measurement that is really an idea in our minds.

Number is an abstract concept which is not defined generally in mathematics.  The numbers can be used for counting .

(countable) An abstract entity used to describe quantity.

A number is a mathematical object used to count, measure, and label.

Planet Math

Number is an abstract concept which is not defined generally in mathematics.  The numbers can be used for counting .
In mathematics one can define different kinds of numbers.

Wolfram Mathworld
The word "number" is a general term which refers to a member of a given (possibly ordered) set. The meaning of "number" is often clear from context (i.e., does it refer to a complex number, integer, real number, etc.?). Wherever possible in this work, the word "number" is used to refer to quantities which are integers, and "constant" is reserved for nonintegral numbers which have a fixed value

Abstract entity

Wiki
A number is a mathematical object used to count, measure, and label.

Mathsisfun

A number is a count or measurement that is really an idea in our minds.

Something to count with!

Wiki+mathsisfun

Mathematical object used to
Count, Measure, Order, Label.

YouTube:

Numberphile

Zermelo- Fraenkel- Axiom
With the axiom of Choice