Ja?cob’s lad?der n. 1. a ladder seen by Jacob in a dream, reaching from the earth to heaven. Gen. 28:12. 2. Naut. a hanging ladder having ropes or chains supporting rungs or steps. [1825?35] Ja?cob’s-lad?der n. any plant of the genus Polemonium, of the phlox family, with cup-shaped blue flowers and paired leaflets in a ladderlike arrangement. [1725?35] Random House Kernerman Webster’s College Dictionary, © 2010 K Dictionaries Ltd. Copyright 2005, 1997, 1991 by Random House, Inc. All rights reserved.