1 : the state of being joined or united or linked
2 : the act of making or becoming a single unit
3 : the act of joining together as one
4 : the state of being a married couple voluntarily joined for life (or until divorce)
5 : a political unit formed from previously independent people or organizations
6 : the shape or manner in which things come together and a connection is made
7 : a connection that fastens things together
8 : the act of bringing two things into contact (especially for communication)