\Se*ba"ceous\, a. [NL. sebaceus, from L. sebum tallow,
grease.] (Physiol.)
Pertaining to, or secreting, fat; composed of fat; having the
appearance of fat; as, the sebaceous secretions of some
plants, or the sebaceous humor of animals.
{Sebaceous cyst} (Med.), a cyst formed by distention of a
   sebaceous gland, due to obstruction of its excretory duct.
{Sebaceous glands} (Anat.), small subcutaneous glands,
   usually connected with hair follicles. They secrete an
   oily semifluid matter, composed in great part of fat,
   which softens and lubricates the hair and skin.