The value of something such as a quality, attitude, or method is its importance or usefulness. If you place a particular value on something, that is the importance or usefulness you think it has.

If you value something or someone, you think that they are important and you appreciate them.

The value of something is how much money it is worth.

When experts value something, they decide how much money it is worth.

You use value in certain expressions to say whether something is worth the money that it costs. For example, if something is or gives good value, it is worth the money that it costs.

The values of a person or group are the moral principles and beliefs that they think are important.

Value is used after another noun when mentioning an important or noticeable feature about something.

A value is a particular number or quantity that can replace a symbol such as 'x' or 'y' in a mathematical expression.