1. (n.) l. (Zool.) One of numerous species of small American singing birds, of the genus Vireo, as the solitary, or blue-headed (Vireo solitarius); the brotherly-love (V. Philadelphicus); the warbling greenlet (V. gilvus); the yellow-throated greenlet (V. flavifrons) and others. See Vireo.

2. (n.) Any species of Cyclorhis, a genus of tropical American birds allied to the tits.