Definition of optional:
free, facultative, unforced, nonmandatory, choice, arbitrary, noncompulsory, with no strings attached, ex gratia, nonobligatory, voluntary, unrestricted, elective, not required, take it or leave it, volitional.
- "A Collection of College Words and Customs", Benjamin Homer Hall.
Cavanaugh, 112 California, the Supreme Court held that any primary election that should become mandatory becomes an election and only those primaries that may be optional with a party as to whether or not they should be held, are not elections.- "Story of the Session of the California Legislature of 1909", Franklin Hichborn.
- "The Geneva Protocol", David Hunter Miller.