anastomosis (n.)

in anatomy, "union or intercommunication of the vessels of one system with those of another," 1610s, medical Latin, from Greek anastomosis "outlet, opening," from anastomoein "to open, discharge" (as one sea into another), "to furnish with a mouth," from ana "again, anew" (see ana-) + stoma "mouth" (see stoma). Related: Anastomotic.