WordNet sense 1 (British biochemist (born in Germany) who isolated and purified penicillin, which had been discovered in 1928 by Sir Alexander Fleming (1906-1979)):

Ernst Boris Chain, Sir Ernst Boris Chain

WordNet sense 2 (a series of hills or mountains):

range, mountain range, chain of mountains, mountain chain, range of mountains

WordNet sense 3 ((chemistry) a series of linked atoms (generally in an organic molecule)):

chemical chain

WordNet sense 4 (a series of things depending on each other as if linked together):

concatenation

WordNet sense 5 (a necklace made by a stringing objects together):

strand, string