Gambling, betting; (now) especially an illegal form of gambling in which bets are taken on the occurrence of numbers in a lottery.
Originally with reference to betting on the opening and closing rates of cotton as transmitted to the Bombay Cotton Exchange from the New York Cotton Exchange.
Late 19th century; earliest use found in The Economist. From Hindi sattā aggregate of seven, seven (in gambling, e.g. of a dice roll or a suit of cards) from Sanskrit saptaka (adjective) consisting of seven, (noun) aggregate of seven from saptan + -ka, suffix forming nouns and adjectives.