A more thorough explanation:

Term: Jactus Retis
Definition: Jactus Retis is a term used in Roman law that refers to the act of casting a net in the context of emptio spei. Emptio spei is a type of contract where the buyer purchases something with the hope that it will be obtained in the future. For example, if a fisherman buys a net with the hope of catching fish in the future, this would be considered an emptio spei contract. The jactus retis refers specifically to the act of casting the net, which is an essential part of the process of trying to catch fish.