Definition of spinetail

• n. - Any one or several species of swifts of the genus Acanthylis, or Chaetura, and allied genera, in which the shafts of the tail feathers terminate in rigid spines.
• n. - Any one of several species of South American and Central American clamatorial birds belonging to Synallaxis and allied genera of the family Dendrocolaptidae. They are allied to the ovenbirds.
• n. - The ruddy duck.