/ Dictionary / Index U Ucayali: Meaning and Definition of Find definitions for: U•ca•ya•li Pronunciation: ("kä-yä'lē), [key] — n. a river in W South America, flowing N from E Peru and joining the Marañón to form the Amazon. 1200 mi. (1930 km) long. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. U.C. Uccello Related Content Daily Word Quiz: cygnet Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language