the trunk or stem of a tree, or that which is like it.-an aperture, with a wooden shutter, in the wall of a house, for giving, occasionally, air or light; also, a small closet.-a measure. see boll, n., 2.-any one of several varieties of friable earthy clay, usually colored more or less strongly red by oxide of iron, and used to color and adulterate various substances. it was formerly used in medicine. it is composed essentially of hydrous silicates of alumina, or more rarely of magnesia. see clay, and terra alba.-a bolus; a dose.