The Latin phrase inter se or inter sese is a legal term that means "between or among themselves." It describes rights and obligations that arise only within a particular group or between individuals, who, in a specific set of circumstances, have similar legal status. It is sometimes used to make a distinction between those who have the rights or obligations and those who do not.
In the US, the law may allow the parties to certain contracts to modify, inter se or between themselves, rights that the law would give them if there were no agreement. For example, a law regulating business partnerships might provide that, in the absence of an agreement inter se, the partners must divide all profits of the partnership equally. This means that if the partners want to give a greater share of the profits to the senior partners than the junior partners, they must make an agreement between themselves to divide the profits in this way. The agreement is made by the members of a specific partnership, and it applies only to them and to that partnership.
Similarly, if a married couple divorce in the US, the property will usually be divided based upon the laws of the state in which the couple lives. Such laws generally provide that if a marriage ends, the property will be divided in a specific way. The law, however, may recognize prenuptial agreements; the couple can agree, before the marriage, that if a divorce occurs, they will divide the property differently than the law would divide it. They have made an agreement inter se or between themselves. The agreement applies only to them, and only if they are married.
The law may create certain inter se rights or obligations among individuals who share a relationship within an organization. The shareholders in corporation A have rights that exist inter se as shareholders in that corporation. The rights arise only among the shareholders of corporation A and not between them and the shareholders of corporation B.
The phrase can also refer to relationships between governments. In Australian law, the phrase inter se is used to describe a dispute concerning the division of power between the government of the commonwealth and the government of one its states. The phrase also arises in discussions of treaties made between nations that are members of the World Trade Organization (WTO). In this context, it refers to agreements made between two or more nations that are members of the WTO.