/ Dictionary / Index R register tonnage: Meaning and Definition of Find definitions for: reg'ister ton"nage Pronunciation: [key] — Naut. Naut. the volume of a vessel, esp. the net tonnage as measured officially and registered for purposes of taxation. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. register ton registrant Related Content Daily Word Quiz: acerbity Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language