Implead – To sue or legally prosecute a person, people, or entitiy (LLC, corporation etc…)
Implead is a term you may see related to insurance because it's often used to describe (especially in legalese) the action of one party, called the plaintiff prosecuting (suing) a defendant.
Another similar word is Impleader. Impleader is also known as "third party procedure". Impleader refers to the civil procedure method of bringing in a third party (an insurance company for example) into an original action (lawsuit), in part, so that two (or more) cases can be decided at one time, saving everyone including the courts time, money, and effort.