BOPEEP n.
The act of looking out suddenly, as from behind a screen, so as to startle some one (as by children in play), or of looking out and drawing suddenly back, as if frightened. I for sorrow sung, That such a king should play bopeep, And go the fools among. Shak.
BRACHYSTOCHRONE n.
A curve, in which a body, starting from a given point, and descending solely by the force of gravity, will reach another given point in a shorter time than it could by any other path. This curve of quickest descent, as it is sometimes called, is, in a vacuum, the same as the cycloid.