Ransom was a type of payment which could be made either with money or goods, in exchange for a hostage.
In 2366, Kova Tholl was unable to provide a reason for his own capture, as he considered himself to not be important enough to hold for ransom. (TNG: "Allegiance")
In 2373, Adin claimed that he was sure that attackers who fired on Tieran's starship wished to take the ship and hold them for ransom. (VOY: "Warlord")