means A hollow container for holding liquids, a ship or large boat, or a tube in the body that carries fluids like blood or sap.

from From Old French 'vaissel,' which came from Late Latin 'vascellum,' a 'small vase' — the diminutive of Latin 'vas,' meaning a vessel or container. So the grand ocean-going ship and the tiny capillary both shrink back to the same humble Latin pot. The biological sense (blood vessels) and the botanical one bloomed later, as people noticed that bodies and plants are full of little tubes ferrying things around — all just containers in motion.