/ Dictionary / Index A Aar: Meaning and Definition of Find definitions for: Aar Pronunciation: (är), [key] — n. a river in central Switzerland, flowing N to the Rhine. 175 mi. (280 km) long. aar Pronunciation: [key] against all risks average annual rainfall. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: aar (Thesaurus) A.A.P.S.S. Aarau Related Content Daily Word Quiz: rustic Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language