/ Dictionary / Index C class inclusion: Meaning and Definition of Find definitions for: class' inclu"sion Pronunciation: [key] — Logic. Logic. the relation between two classes in which all members of one class are included in the other, as in the proposition “All humans are animals.” Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. classify class interval Related Content Daily Word Quiz: panacea Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language