Definitions:
the action of joining together or the fact of being joined together, especially in a political context

a society or association formed by people with a common interest or purpose

a political unit consisting of a number of states or provinces with the same central government.

the set that comprises all the elements (and no others) contained in any of two or more given sets.

a joint or coupling for pipes.

(in south asia) a local administrative unit comprising several rural villages.

a part of a flag with an emblem symbolizing national union, typically occupying the upper corner next to the staff.

a fabric made of two or more different yarns, typically cotton and linen or silk.