Definition of pen-tailed in US English:

pen-tailed

adjective

Zoology
  • Having a tail resembling a feather, or a quill pen. Chiefly in "pen-tailed tree shrew"noun a very small tree shrew, Ptilocercus lowii (family Tupaiidae), of the Malay Peninsula, Sumatra, and Borneo, having a fringe of long, stiff hairs at the end of its tail.

Origin

Mid 19th century; earliest use found in Mary Somerville (1780–1872), science writer and mathematics expositor. From pen + tailed.

Pronunciation

pen-tailed

/ˈpɛnteɪld/