Which legal term derives from the Latin verb 'to pledge'?

Affidavit refers to a written promise, and its Latin roots connect it to another kind of promise in English. It comes from a past tense form of the Latin verb "affidare", meaning “to pledge”. An affidavit is always a sworn written document. If it contains a lie, the person making it may be prosecuted. Affidavits are often used in court when it isn't possible for someone to appear in person. Police officers must usually file an affidavit with a judge to get a search warrant. Affidavits (unlike similar signed statements called depositions) are usually made without an opposing lawyer being present and able to ask questions.

Source: Merriam Webster