Entry 1 sense Webster, 1913 Bitters /bĭt'-ẽrz/ · Bit·ters · IPA /bˈɪtərz/ 01 n. pl. A liquor, generally spirituous in which a bitter herb, leaf, or root is steeped. 1. A liquor, generally spirituous in which a bitter herb, leaf, or root is steeped.