/ Dictionary / Index V Valles Marineris: Meaning and Definition of Find definitions for: Val'les Mar•i•ner'is Pronunciation: (val'us-mar"u-nâr'is), [key] — Astron. Astron. a canyon on Mars, 3100 mi. (5000 km) in length, named after the Mariner spacecraft. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. Vallenar Valletta Related Content Daily Word Quiz: banshee Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language