Kenneth G. Wilson (1923). The Columbia Guide to Standard American English. 1993.
sack (n.)
Most senses of the noun are Standard. The firing from a job sense and the bed or bedroll sense, however, are slang, best limited to Conversational and Informal use, and sack meaning a base in baseball and the tackling of a quarterback behind the line of scrimmage are sports jargon. See BAG (2).