A connection between two things that normally diverge. The term describes physiological openings between cavities or passages inside a living organism (such as our intestines), but can also be applied in geology, geography, and architecture. When the connection is abnormal, it’s known as a fistula.
The word “anastomosis” originated in the year 1541. It is derived from Late Latin and Greek, from “anastomoun” (to provide with an outlet) and from “stoma” (mouth, opening).