Answer: aggers

AnswerCrossword Clue
AGGERSRoman ramparts.
AGGERSOld earthworks.
aggersAGGER, a mound of earth used as protection
aggers(in ancient Roman building) an earthen mound or rampart, esp. one having no revetment
aggersa. high tide in which the water rises to a certain level, recedes, then rises again b. low tide in which the water recedes to a certain level, rises slightly, then recedes again