(n): the activities of educating or instructing; activities that impart knowledge or skill
(n): a connected series of events or actions or developments
(n): similar things placed in order or happening one after another
(n): general line of orientation
(n): a line leading to a place or point
(n): a mode of action
(n): something done (usually as opposed to something said)
(n): a line or route along which something travels or moves
(n): a spatial location defined by a real or imaginary unidimensional extent
(n): a body of students who are taught together
(n): a group of persons together in one place
(n): part of a meal served at one time
(n): a source of materials to nourish the body
(n): (construction) a layer of masonry
(n): single thickness of usually some homogeneous substance
(n): facility consisting of a circumscribed area of land or water laid out for a sport
(n): a building or place that provides a particular service or is used for a particular industry
(v): move swiftly through or over
(v): travel across or pass over
(v): move along, of liquids
(v): move so as to change position, perform a nontranslational motion
(v): hunt with hounds
(v): pursue for food or sport (as of wild animals)
On a stringed instrument, strings that are grouped closely together so that they are fretted or stopped at the same time. A twelve-string guitar is said to have six double courses. Some lutes and older stringed instruments (and the modern 8-string bass) have triple or treble courses.
Edit: I should have said that the 12-string bass has four treble courses. The 8-string bass has four double courses.