An Etymological Dictionary of Astronomy and Astrophysics

1. The part that sticks out at the back of an animal’s body, and that it can move.
   

2. Anything resembling such an appendage in form or position.
   

3. → cometary tail.

Etymology (EN): M.E.; O.E. tægl, from P.Gmc. *tagla- (cf. O.H.G. zagal, Ger. Zagel “tail,” O.N. tagl “horse’s tail”).

Etymology (PE): Dom, variant domb, “tail;” Mid.Pers. dumb “tail;” Av. duma- “tail”; donbâlé, from domb + -âlé, -âl resemblance suffix, → -al.