WordNet (r) 3.0 (2006):

Sermon on the Mount
    n 1: the first major discourse delivered by Jesus (Matthew 5-7
         and Luke 6:20-49)

Easton's 1897 Bible Dictionary:

Sermon on the mount
   After spending a night in solemn meditation and prayer in the
   lonely mountain-range to the west of the Lake of Galilee (Luke
   6:12), on the following morning our Lord called to him his
   disciples, and from among them chose twelve, who were to be
   henceforth trained to be his apostles (Mark 3:14, 15). After
   this solemn consecration of the twelve, he descended from the
   mountain-peak to a more level spot (Luke 6:17), and there he sat
   down and delivered the "sermon on the mount" (Matt. 5-7; Luke
   6:20-49) to the assembled multitude. The mountain here spoken of
   was probably that known by the name of the "Horns of Hattin"
   (Kurun Hattin), a ridge running east and west, not far from
   Capernaum. It was afterwards called the "Mount of Beatitudes."