any of numerous small, chiefly Old World birds of the family Motacillidae, having a slender body with a long, narrow tail that is habitually wagged up and down.
2.
any of several similar birds, as the water thrushes of the genus Seiurus.
any of various passerine songbirds of the genera Motacilla and Dendronanthus, of Eurasia and Africa, having a very long tail that wags when the bird walks: family Motacillidae