chain, concatenation -- (a series of things depending on each other as if linked together; "the chain of command"; "a complicated concatenation of circumstances")
chain, chemical chain -- ((chemistry) a series of linked atoms (generally in an organic molecule))
chain -- (a series of (usually metal) rings or links fitted into one another to make a flexible ligament)
chain -- ((business) a number of similar establishments (stores or restaurants or banks or hotels or theaters) under one ownership)
chain -- (anything that acts as a restraint)
chain -- (a unit of length)
Chain, Ernst Boris Chain, Sir Ernst Boris Chain -- (British biochemist (born in Germany) who isolated and purified penicillin, which had been discovered in 1928 by Sir Alexander Fleming (1906-1979))