A raglan sleeve is a sleeve that extends in one piece fully to the collar, leaving a diagonal seam from underarm to collarbone.[1] The ancient Chiton was a tunic worn by men and women of ancient Greece and Rome that fastened at the shoulder resembling a raglan sleeve with a peplum waist line.
^Quinion, Michael. "Cardigan". World Wide Words. Retrieved 13 January 2013. Another item whose name appeared at the time was the raglan, a type of overcoat named after Lord Raglan, a British general in the Crimea. The garment was unusual in that the sleeves continued in one piece up to the neck, producing a larger, looser armhole that suited the one-armed general.
^ abOxford English Dictionary Third edition, (2008) online version September 2011, retrieved 7 November 2011. An entry for this word was first included in New English Dictionary, 1903.