A constant, set at $100, which when multiplied by the cash index value gives the dollar value of the stock index underlying an option . That is, dollar value of the underlying stock index = cash index value x $100 (the options contract multiple).
OPTIONS CONTRACT MULTIPLE
Meaning of OPTIONS CONTRACT MULTIPLE in English
Campbell R. Harvey. Hypertextual finance English glossary. Английский словарь гипертекстовых финансов. 2012