A gambeson (or aketon or padded jack) is a padded defensive jacket, worn as armour separately, or combined with mail or plate armour. Gambeson were produced with a sewing technique called quilting. Usually constructed of linen or wool, the stuffing varied, and could be for example scrap cloth or horse hair. During the 14th century, illustrations usually show buttons or laces up the front.
The term gambeson is a loan from Old French gambeson, gambaison, originally wambais, formed after the Middle High German term wambeis "doublet", in turn from Old High German wamba "stomach" (cognate to womb.) The term aketon, originally medieval french alcottonem might be a loan from Arabic al-qutn "cotton (definite article - the cotton)". In medieval Norse, the garment was known as vapntreyiu, lit. "arming shirt" or pannzar/pannzarum, another loan word from middle high German. Also known as: Aketon, acton, arming coat, auqueton, gambeson, hacketon, haqueton, pannzar, vapntreiyu, wambais, wambesium, or wambs.