/ Dictionary / Index C class interval: Meaning and Definition of Find definitions for: class' in"terval Pronunciation: [key] — Statistics. Statistics. one of a set of intervals of arbitrary width into which the range of a sample of measurement is partitioned. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. class inclusion classis Related Content Daily Word Quiz: abstain Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language