/ Dictionary / Index A alkali rock: Meaning and Definition of Find definitions for: al'kali rock" Pronunciation: [key] — Mineral. Mineral. any igneous rock with a marked preponderance of alkali and a low percentage of silica. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. alkalinity alkali soil Related Content Daily Word Quiz: cautious Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language