It is sox instead of socks because they want to be noticed a bit more so they can be remembered to be unique. The White Sox is spelled like this, too. The main reason is to be popular and different in their own way.
Basically the name was shortened to fit easier into newspaper headlines back in the early 20th century ...sorry above answer it wasn't to be unique
Same way the Mets real name is the Metropolitans
Up until 1908, the Red Sox were called the Boston Americans to differentiate them from the Boston Nationals. The Nationals decided to start the 1908 season with blue socks instead of their drab red socks. The Americans upon hearing of this, decided to change to a bright red sock (scandelous then!) and take up the name Red Sox.
The team is called Boston Red "Socks."
The Boston Red Socks
RED
In 2009 the Boston Red Socks hit 212 home runs
Boston red socks
Massachusetts
17 to 26 Boston
RED SOCKS im a Boston gal yous guys!
from the Indians the red socks oh and hi
In 2009 the Boston Red Socks hit 212 home runs
Boston the Yankees have a brand new stadium