Aa, the name of a large number of small European rivers. The word is derived from the Old German aha, cognate to the Latin aqua, water (cf. Ger.-ach; Scand. a, aa, pronounced o). The following are the more important streams of this name:
- two rivers in the west of Russia, both falling into the Gulf of Riga, near Riga, which is situated between them
- a river in the north of France, falling into the sea below Gravelines, and navigable as far as St. Omer
- a river of Switzerland, in the cantons of Lucerne and Aargau, which carries the waters of Lakes Baldegger and Hallwiler into the Aar
- in Germany there are the Westphalian Aa, rising in the Teutoburger Wald, and joining the Werre at Herford, the Munster Aa, a tributary of the Ems, and others.
- in the Netherlands, a river in Groningen province that flows through Groningen city.
From Gutenberg Encylopedia (1911)