Most significant other is a term that is sometimes used in the context of a hierarchical polyamorous relationship to refer to one's primary partner. The term indicates that while one may have several partners who they identify as their "significant others," this specific partner holds a place of greater importance or priority.
This term is not exclusive to the the polyamorous community. The idea of one person holding a position of primary importance in another's life can be understood by many people. Another term that may be used is primary relationship.
This definition explains the meaning of Cishet and why it matters.
Find out what a fraysexual is - and how it fits into the asexuality spectrum.
What is Comphet? - Definition from Kinkly
This definition explains the meaning of Omega Male and why it matters.
This definition explains the meaning of Apistia and why it matters.
This definition explains the meaning of Dyscalligynia and why it matters.
This definition explains the meaning of Secondary Relationship and why it matters.
This definition explains the meaning of Sexual Double Standard and why it matters.