prostomium

== English == === Etymology === From Ancient Greek, meaning "before the mouth". === Noun === prostomium (plural prostomia) (zoology) The portion of the head of an annelid situated in front of the mouth. ==== Related terms ==== prostomial === References === “prostomium”, in Webster’s Revised Unabridged Dictionary, Springfield, Mass.: G. & C. Merriam, 1913, →OCLC.