A general description is provided of the "geometric dictionary," a graphic display aid, used by the Computer-Assisted Instruction Laboratory at the Pennsylvania State University. The purpose of the description is to enable the reader to duplicate and use the dictionary on any cathode ray tube terminal of the IBM 1500 system. The major advantages and disadvantages of the geometric dictionary are first discussed and a brief general overview given. Following this, details are presented regarding the steps of sketching, coding, and entering which are involved in the construction of line drawings. Information is also provided about keyboard functions, dictionary changes and the inclusion of text, blank characters, and shading. (PB)