Originally Posted by Apple22over7:
“Maybe it was to avoid confusion with a Jersey? They’re similar garments, and having two separate and distinct definitions would ease the explanation somewhat.”
A Jersey and a Guernsey are both knitted jumpers with totally different patterns. Note the capital letters for for jumpers/sweaters in those patterns.
The Guernsey jumper has been around since the 16th century. The Austalian guernsey shirt for football is modern by comparison.
Tops worn by sportsmen such as cycling and soccer are also called jerseys.
Then there's the Guernsey cow which produces very rich milk.