Gun pills: why is it called a .38 Special?

Why the .38 Special is defined as "Special", and is  a .38, even if it shoots a .357 caliber bullet?

A History of Carry: 40 Years Armed - Guns and Ammo

Ammunition, Page 3

38 Super: The Semi-Auto .38 That's Slipping Into Obscurity

A History of the Iconic .38 Special - The Shooter's Log

S&W Snub-Nose Bicycle Revolvers — Elegant and Vintage - Firearms News

Colt Detective Special - Internet Movie Firearms Database - Guns

38 caliber

Colt, Page 2

Technics

BTI Brands, Page 2

Tays Realty & Auction - Auction: ONLINE ABSOLUTE AUCTION: 300

Colt Detective Special - Internet Movie Firearms Database - Guns

/sites/default/files/styles/medium/pub