Vector-boson fusion is a process in particle physics where two vector bosons, such as W or Z bosons, fuse together to produce a new particle. This process is important in the study of electroweak interactions and plays a key role in the production of particles like the Higgs boson in high energy collider experiments. Vector-boson fusion is also studied as a way to search for new physics beyond the standard model of particle physics. The study of vector-boson fusion can provide valuable insights into the fundamental forces and interactions of the universe.