bromide (n.)
compound of bromine and another metal or radical, 1836, from bromine, the pungent, poisonous element, + -ide. Used as a sedative; figurative sense of "dull, conventional person or trite saying" popularized by U.S. humorist Frank Gelett Burgess (1866-1951) in his book "Are You a Bromide?" (1906). Related: Bromidic.