/ Dictionary / Index L length between perpendiculars: Meaning and Definition of Find definitions for: length' between" perpendic'ulars Pronunciation: [key] — Naut. Naut. the length of a hull between the forward and after perpendicular. Cf. perpendicular (def. 11). Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. length lengthen Related Content Daily Word Quiz: arboreal Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language