An Etymological Dictionary of Astronomy and Astrophysics

1. A series of usually metal links passing through one another, used for various purposes.
   

2. A series of things connected or following in succession. → chain reaction; → proton-proton chain.

Etymology (EN): Chain, from O.Fr. chaeine, from L. catena “fetter.”

Etymology (PE): Zanjir from Mid.Pers. zanjir “chain;” zanjiré, from zanjir + nuance suffix -é.