set sail verb3 •To depart on a voyage by boat or ship.We set sail for the Caribbean. •(figurative) To do the analogous counterpart on a vessel with any other means of propulsion, such as steaming.A Navy task force is expected to set sail shortly. •To spread and arrange the sails of a sailboat or sailing ship for the purpose of putting out.The sailors of the regatta are going to wait out this weather before they set sail. formssetting sail · sets sail