Pronunciation: (wôr'blur),[key] —n. 1. any of several small, chiefly Old World songbirds of the subfamily Sylviidae. Cf. blackcap (def. 1), reed warbler. 2. Also called wood warbler. any of numerous small New World songbirds of the family Parulidae, many species of which are brightly colored. Cf. yellow warbler. 3. a person or thing that warbles.