a person or thing that acts, happens, or exists in such a way that some specific thing happens as a result; the producer of an effect

You have been the cause of much anxiety. What was the cause of the accident?

the reason or motive for some human action

The good news was a cause for rejoicing.

good or sufficient reason

to complain without cause; to be dismissed for cause.

Law .

a ground of legal action; the matter over which a person goes to law.

a case for judicial decision.

any subject of discussion or debate.

a principle, ideal, goal, or movement to which a person or group is dedicated

the Socialist cause; the human rights cause.

the welfare of a person or group, seen as a subject of concern

support for the cause of the American Indian.

Philosophy .

the end or purpose for which a thing is done or produced.

Aristotelianism . any of the four things necessary for the movement or the coming into being of a thing, namely a material (material cause), something to act upon it (efficient cause), a form taken by the movement or development (formal cause), and a goal or purpose (final cause).

to be the cause of; bring about. ?

make common cause

to unite in a joint effort; work together for the same end

They made common cause with neighboring countries and succeeded in reducing tariffs.