/ Dictionary / Index J Jacob's staff: Meaning and Definition of Find definitions for: Ja'cob's staff' Pronunciation: [key] — pl. Jacob's staves. cross-staff. a pole providing a firm support for a compass or other instrument. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. Jacobson's organ jacobus Related Content Daily Word Quiz: censure Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language