An Etymological Dictionary of Astronomy and Astrophysics

1. General: Something that indicates a border or limit; the border or limit so indicated.
   

2. Thermodynamics: A conceptual closed surface useful in separating and distinguishing a system from its surroundings.
   

3. Math.: In topology, the boundary of a subset S of a topological space X is the set of points which can be approached both from S and from the outside of S.
   

4. Electronics: An area of meeting of P-type and N-type → semiconductor materials where the → donor and → acceptor concentrations are equal.

Etymology (EN): From Fr., from O.Fr. bodne, from M.L. bodina, butina “boundary, boundary marker.”

Etymology (PE): Karân, karâné, kenâr from Mid.Pers. karânag, Av. karana- “boundary.”