A more thorough explanation:

A cause of action is a legal term that refers to a set of facts that allow a person to seek a legal remedy. These facts can come from a constitution, statute, judicial precedent, or administrative regulation. In other words, a cause of action is a legal reason for a person to sue someone else.

For example, in New York, the cause of action for conversion requires two factual elements: (1) the plaintiff's possessory right or interest in the item, and (2) the defendant's dominion over that item or interference with it in derogation of the plaintiff's rights. This means that if someone takes something that belongs to you without your permission, you can sue them for conversion.

Similarly, in California, the elements for conversion are (1) the plaintiff's ownership or right to possession of the property, (2) the defendant's conversion by a wrong act or disposition of plaintiff's property rights, and (3) damages suffered by the plaintiff. This means that if someone takes your property and sells it without your permission, you can sue them for conversion.

These examples illustrate how a cause of action is a legal reason for a person to sue someone else. In both cases, the plaintiff has a legal right to the property that was taken, and the defendant has interfered with that right in some way. By proving these facts, the plaintiff can seek a legal remedy, such as damages or the return of the property.