What is the meaning of 'cause' in the cause of peace?

Does it mean an 'organization' or a 'belief'?

For examples:

The donation is the biggest private gift to a humanitarian cause.

Animal welfare campaigners raised £70000 for their cause last year.

a good cause (= an organization that does good work, such as a charity).

fighting for the Republican cause.

What do the causes mean? organizations or beliefs?

Thank you very much indeed.
This will help you:
cause, n., v., caused, caus·ing.
1. 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?
2. the reason or motive for some human action: The good news was a cause for rejoicing.
3. good or sufficient reason: to complain without cause; to be dismissed for cause.
4. Law.
a. a ground of legal action; the matter over which a person goes to law.
b. a case for judicial decision.
5. any subject of discussion or debate.
6. a principle, ideal, goal, or movement to which a person or group is dedicated: the Socialist cause; the human rights cause.
7. the welfare of a person or group, seen as a subject of concern: support for the cause of the American Indian.

8. Philos.
a. the end or purpose for which a thing is done or produced.
b. 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).
9. 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.

"In the cause of peace". = In this phrase cause means that "peace" is the goal.

"They worked in the cause of world peace" = They worked with the hope that the work would lead to world peace.

AnonymousWhat do the causes mean? organizations or beliefs?

A cause is more a reason rather than a belief or organisation. The reason we are doing this work is that we hope to obtain world peace.
Cause has a similar function to "because".

Causes can also be campaigns. So the Republican cause is the Republican campaign.

This link may help your understanding.