Jā'cob's-lād'der, n.
n. 1. (Bot.) A plant of the genus Polemonium (P. cæruleum), having numerous flowers of a blue or white color, somewhat drooping. P. reptans is common in the United States, and has blue flowers. Gray.
Sense 2. (Naut.) A rope-ladder, with wooden steps, for going aloft. R. H. Dana.