wagtail Meaning, Definition & Usage

  1. noun Old World bird having a very long tail that jerks up and down as it walks

WordNet

Wag"tail` noun
Definitions
  1. (Zoöl.) Any one of many species of Old World singing birds belonging to Motacilla and several allied genera of the family Motacillidæ. They have the habit of constantly jerking their long tails up and down, whence the name.

Webster 1913