undefined (mathematics)

In mathematics, the word undefined has several different meanings, depending on the context.

• In geometry, simple words such as "point" and "line" are taken as undefined terms.
• In arithmetic, some arithmetic operations are called "undefined". Two of the more famous examples are division by zero and zero to the power of zero.
• In algebra, a function is said to be "undefined" at points not in its domain. For example, in the real number system, is undefined for negative , i.e., no such values exist for function .