Usually it means "Smith & Wesson"
Question can't be answered without knowing the caliber.
Old gun catalogs and magazines
500 s&w
Impossible to know the caliber with only a serial number. It should be marked on the barrel.
the maker.
Assuming you mean caliber, the caliber simply refers to the diameter of the bullet the gun is designed to fire. American cartridge sizes are expressed as tenths or hundredths of an inch, and European cartridges sizes are expressed as millimeter. A .40 caliber gun fires a bullet that is .40 of an inch in diameter. A 9 millimeter gun fires a bullet that is 9 millimeters in diamter. There are too many variations to list here, but some common handgun calibers are 9 millimeter, 10 millimeter, .40 SW, .38 special, .44 magnum, .45 ACP, .380 ACP.
50-175 USD
10-200 USD or so
NO, NO, NO, NO, NO, NO, NO!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! DO NOT EVEN TRY TO DO THIS!!!!!!!!!!!!!!
When referring to the .40 caliber cartridge, SW always stands for Smith and Wesson, regardless of the brand of the gun, because the .40 S&W cartridge was designed by Smith and Wesson. The offical name of the cartridge is .40 S&W, just like the official name of the .45 is .45 ACP (Automatic Colt Pistol). People have a habit of leaving off things they don't think are important, so the .40 S&W is commonly called just "40."
100-550 USD
100-400 or so