If you appeal to someone to do something, you make a serious and urgent request to them.

An appeal is a serious and urgent request.

An appeal is an attempt to raise money for a charity or for a good cause.

If you appeal to someone in authority against a decision, you formally ask them to change it. In British English, you appeal against something. In American English, you appeal something.

An appeal is a formal request for a decision to be changed.

If something appeals to you, you find it attractive or interesting.

The appeal of something is a quality that it has which people find attractive or interesting.