If you apply for something such as a job or membership of an organization, you write a letter or fill in a form in order to ask formally for it.

If you apply yourself to something or apply your mind to something, you concentrate hard on doing it or on thinking about it.

If something such as a rule or a remark applies to a person or in a situation, it is relevant to the person or the situation.

If you apply something such as a rule, system, or skill, you use it in a situation or activity.

A name that is applied to someone or something is used to refer to them.

If you apply something to a surface, you put it on or rub it into the surface.

When the driver of a vehicle applies the brakes, he or she uses them to slow the vehicle down or to stop it from moving.