Definitions

1. noun

A person or state that is equally or jointly sovereign with another; a sovereign in a shared sovereignty or a system of dual or joint sovereignty.

“The cosovereign states signed a treaty to maintain peace and security in the region.”

2. adjective

Describing a sovereign in a shared sovereignty or a system of dual or joint sovereignty.

“The cosovereign powers of the monarch and the parliament were balanced to ensure stability in the government.”