From Wikipedia: "Quarterback sack".
The term "Quarterback sack" was first coined by Hall of Fame defensive end Deacon Jones. Jones, who played in the NFL from 1961 to 1974, felt that a sack devastated the offense in the same way that a city was devastated when it was sacked. However, the term "sack" was not widely used before ca. 1970; previously one would simply refer to a player's being tackled behind the line (of scrimmage), in so many words.