An Etymological Dictionary of Astronomy and Astrophysics

1. A tube or duct, as an artery or vein, containing or conveying blood or some other body fluid.
   

   2. Botany: A duct formed in the xylem, composed of connected cells that have lost their intervening partitions, that conducts water and mineral nutrients (Dictionary.com).

Etymology (EN): M.E., from O.Fr. vessel “container, receptacle; ship,” from L.L. vascellum “small vase or urn,” also “a ship,” alteration of L. vasculum, diminutive of vas “vessel.”

Etymology (PE): 1) Rag “blood vessel, vein; lineage, race, stock,” from Mid.Pers. rag, from Proto-Iranian *raha-ka-, from *raha- “liquid, essence,” + suffix -ka-; cf. Av. ranhā- “name of a mythical stream;” Skt. rása- “juice (of plants), liquid, essence,” rásavant-, rasin- “juicy;” L. ros “dew;” Lith. ràsa “dew;” O.C.S. rosa “dew.”

2. Âvand “vessel,” contraction of âbvand, literally “water utensil,” from âb, → water, + vand “vessel, vase, cup,” from bastan “to bind, shut,” → shutter.