Entry 1 sense Webster, 1913 Bromalin · Bro·ma·lin · IPA 01 n. A colorless or white crystalline compound, (CH2)6N4C2H5Br, used as a sedative in epilepsy. 1. A colorless or white crystalline compound, (CH2)6N4C2H5Br, used as a sedative in epilepsy.(Pharm.)