/ Dictionary / Index T tree line: Meaning and Definition of Find definitions for: tree' line" Pronunciation: [key] timberline. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. tree lawn treelined Related Content Daily Word Quiz: tenacious Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language