A more thorough explanation:

Pecunia trajectitia is a Latin term that means "money conveyed overseas." In Roman law, it refers to money loaned in connection with the transport of goods by ship, with the lender bearing the risk of loss.

For example, if a merchant needed to transport goods from Rome to Alexandria, they might borrow pecunia trajectitia to pay for the cost of shipping. If the ship sank or the goods were lost, the lender would bear the loss, not the borrower.

Nauticum fenus is a Latin term that means "nautical interest." In Roman and civil law, it refers to a loan to finance the transport of goods by sea, specifically a loan on bottomry made to a transporter of merchandise by ship.

For example, if a merchant needed to transport a valuable cargo of spices from India to Rome, they might borrow nauticum fenus to pay for the cost of shipping. The loan is subject to an extremely high rate of interest because it does not have to be repaid unless the ship safely reaches its destination. The nauticum fenus is both a loan and marine insurance.

The rate, originally unlimited because of the risks of sea travel, was eventually fixed at 12%. The money loaned is pecunia trajecticia (money conveyed overseas).