quadrivalent

1. not comparablechemistryHaving a valence of four.
2. not comparablemedicineProtecting against four different (usually influenza) viruses.
3. not comparablegraph theoryHaving all of its vertices of degree four.

   In graph theory terms, a regular projection of a knot, or knot diagram is thus a quadrivalent planar graph with over/under-decorated vertices.

   2020 January 3, Wikipedia contributors, “Knot (mathematics)”, in English Wikipedia, Wikimedia Foundation

plural quadrivalents

1. biologyAny quadrivalent chromosome