/ Dictionary / Index J jack truss: Meaning and Definition of Find definitions for: jack' truss" Pronunciation: [key] any of a number of trapezoidal trusses for supporting those areas of a hip roof not beneath the peak or ridge, parallel to the truss or trusses that meet at the peak or ridge. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. jack towel jack-up Related Content Daily Word Quiz: blithesome Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language