Webster’s Revised Unabridged Dictionary · 1913
Vas
Vas, n.; pl. Vasa (#). [L., a vessel. See Vase.] (Anat.) A vessel; a duct.
Vas deferens; pl. Vasa deferentia. [L. vas vessel + deferens carrying down.] (Anat.) The excretory duct of a testicle; a spermatic duct.