1. A city of southwest England on Plymouth Sound, an inlet of the English Channel. A major port, it was the embarkation point for the fleet that fought the Spanish Armada (1588).

2. A town of southeast Massachusetts on Plymouth Bay, an inlet of the Atlantic Ocean, southeast of Boston. Founded in 1620 by Pilgrims, who supposedly set foot on Plymouth Rock when disembarking from the Mayflower, it was the center of Plymouth Colony. The colony was governed under precepts laid down in the Mayflower Compact until 1691, when it was absorbed by the royal colony of Massachusetts.