/ Dictionary / Index L Lassen Peak: Meaning and Definition of Find definitions for: Las'sen Peak' Pronunciation: (las'un), [key] an active volcano in N California, in the S Cascade Range. 10,465 ft. (3190 m). Also called Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. Lassalle Lassen Volcanic National Park Related Content Daily Word Quiz: mamba Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language