Vessel (French vaissel, from a rare Latin vascellum, diminuitive of vas, vase, or urn), a word of somewhat wide application for many objects, the meaning common to them being capacity to hold or contain something.

Thus it is a general term for any utensil capable of containing liquids, and for those tubular structures in anatomy, such as the arteries, veins or lymphatics, which contain, secrete or circulate the blood or lymph. Organs or structures which are largely supplied with vessels are said to be vascular (Latin vasculum, another diminutive of vas).

Vessel (as in French) is also a general term for all craft capable of floating on water larger than a rowing boat, such as ships.

The word is also familiar in Biblical phraseology in the figurative sense of a person regarded as the recipient of some Divine dispensation, a chosen vessel, or as one into which something is infused or poured, vessel of wrath.

A pressure vessel is a vessel that is subject to either internal or external pressure. This definition generally includes air receivers, heat exchangers, evaporators, steam type sterilisers and autoclaves.