This international Standard defines standard notations for structural design. It covers general terms which are necessary to this field of application and, in general, excludes terms relevant to a particular material or to a particular technica field. It indicates only the symbols to be used without prejudice to the exact definition of each term, which is within the scope of other International Standards. Table I gives general indications about the usage of different types of letter. Tables 2, 3 and 4 give letters to be used as a main symbol and their meanings. Table 5 gives a list of special and mathematical symbols. Tables 6 gives letters or groups of letters when used as subscripts and their meanings.