1: any of a genus (Polemonium) of herbs of the phlox family that have pinnate leaves, a bell-shaped corolla, and a several-seeded capsule especially: a perennial herb (P. caeruleum) with bright blue or occasionally white flowers
2: a marine ladder of rope or chain with wooden or iron rungs
First Known Use of Jacob's ladder
1733, in the meaning defined at sense 1
History and Etymology for Jacob's ladder
from the ladder seen in a dream by Jacob in Genesis 28:12