bro·mo·phenol blue \| ̷ ̷ ̷ ̷ at bromo-+...-\noun alsobrom·phenol blue\(ˈ)brōm+...-\ Etymology: International Scientific Vocabulary brom- + phenol : a dye C19H10Br4O5S obtained as pinkish crystals and used as an acid-base indicator; tetrabromo-phenolsulfonephthalein