Meaning

noun a series of things depending on each other as if linked together

noun (chemistry) a series of linked atoms (generally in an organic molecule)

noun a series of (usually metal) rings or links fitted into one another to make a flexible ligament

originFrom Middle English cheyne, chaine, from Old French chaine, chaene (“chain”), from Latin catēna (“chain”), from Proto-Indo-European *kat- (“to braid, twist; hut, shed”). Doublet of catena. Displaced native Middle English rakil and rakent (from Old English racente (“chain”)); see rackan.

Etymology from Wiktionary, CC BY-SA 3.0