uil·leann pipe also uil·lean pipe 
(ĭlən, -yən)
(ĭlən, -yən)n. often uilleann pipes
A Celtic bagpipe whose air supply is produced by a bellows held under the arm and operated by the elbow.
[Irish Gaelic, genitive of uillinn, elbow, from Old Irish uilenn; see el- in the Appendix of Indo-European roots.]