Pseudovirus is a term used to describe a virus-like particle that lacks the ability to replicate and infect living cells. There are several other terms that refer to similar structures, including virus-like particles, protein capsids, and virus mimics. Virus-like particles (VLPs) are similar to pseudoviruses, but they are typically derived from the natural viral structure and can sometimes retain the ability to infect cells. Protein capsids are structures composed of viral proteins that can self-assemble into a virus-like particle. Virus mimics are synthetic particles that mimic the shape and size of viruses, but lack the genetic material necessary for infection. All of these structures are useful for studying viral interactions and developing vaccines.