Denoting the presence of hair in a dermoid cyst or in a sinus opening on the skin. ... Origin: pilo-+ L. Nidus, nest ... (05 Mar 2000) ... 
(pi″lo-ni´dәl) having a cluster of hairs.
Type: Term Pronunciation: pī-lō-nī′dăl Definitions: 1. Denoting the presence of hair in a dermoid cyst or in a sinus opening on the skin.
Pilonidal: Refers to an embedded (ingrown) hair or tuft of hair. Literally, a nest of hair. From the Latin pilus (meaning hair) and nidus (meaning nest).
pilonidal 1. Pertaining to, characterized by, or having a nidus or tuft of hairs. 2. A reference to a cyst containing hair as a nucleus or nidus.