agger

plural aggers

1. A double tide, particularly a high tide in which the water rises to a given level, recedes, and then rises again (or only the second of these high waters), but sometimes equally a low tide in which the water recedes to a given level, rises, and then recedes again

   A double tide or agger is a high tide consisting of two maxima of nearly the same height, separated by a relatively small depression; or a low tide consisting of two minima separated by a relatively small elevation.

   1969, United States. Naval Oceanographic Office, Navigation Dictionary, page 254

   2 more examples

   The phænomenon of long continued high water or double high water in estuaries is, we believe, not uncommon. [...] The first high water appears to be considered by the Dutch, in common language, as the real high water, and the second is called the agger, but so little difference is there between them, that, in making the extensive series of simultaneous tide-observations proposed by Mr. Whewell, the agger was sometimes observed for high water.

   1845, George Biddell Airy, Tides and Waves, page 375

   [page 62:] As can be seen [...], once the water has reached the lowest level, it remains low for some time. After rising slightly, it then drops again and a second low tide follows. Only then does the water rise quickly and the flood sets in. A slight rise like this followed by a drop is called an agger or a double tide. […] [page 279:] […] these 'overtones' may cause the phenomena of agger or double high water […]

   2006, Huibert-Jan Lekkerkerk, Handbook of Offshore Surveying

2. historicalSynonym of earthwork in ancient Roman contexts, particularly a defensive wall or mound.

   By the Augustan period, however, the old ashlar circuit with its earthen agger was beginning to be dismantled in some places.

   2012, Seth G. Bernard, “Continuing the Deabte on Rome's Earliest Circuit Walls”, in Papers of the British School at Rome, number 80, page 2

   Synonyms: earthwork in ancient Roman contexts, particularly a defensive wall or mound

1. A surname from Danish.

   But the Danes remained resolute in defence - largely thanks to a spirited display by captain Daniel Agger - and they went ahead with their first meaningful attack.

   2012 June 9, Owen Phillips, “Euro 2012: Netherlands 0-1 Denmark”, in BBC Sport, archived from the original on 09 Sep 2025