The diamond-shaped pattern especially associated with knitted socks and sweaters is argyle.
Argyle consists of overlapping diamonds or lozenges, usually arranged with diagonal lines crossing the shapes. Its name and broad inspiration are linked to Argyll in western Scotland, including the tartan traditions associated with Clan Campbell and the patterned hose worn by Scottish Highlanders.
Modern argyle knitwear became fashionable in Britain after the First World War and then spread widely in the United States. Pringle of Scotland helped popularize it, while the Duke of Windsor made argyle sweaters and socks prominent in golf and country-sport clothing. The pattern’s association with socks also reflects the popularity of plus-fours, which exposed long knitted socks below the knee.
Argyle is not simply any diamond print. Traditional argyle usually combines layered diamonds with contrasting diagonal overlaid lines. In knitting, it is often made with intarsia, a technique that manages separate color sections. Tartan and argyle may share Scottish associations, but their construction and visual organization differ.