Technically, the differences between an aceton and a gambeson are minimal, as both serve as padded textile armor for shock absorption. Historically, the term aceton is often used for something worn under armor (derived from the Arabic al-qutn for cotton), while gambeson is more commonly used on the European continent or for standalone armor.
This armor doublet is ideally suited as an undergarment for plate armor or chainmail due to its fastening points, as the armor pieces can be attached directly to the doublet, which also protects against pressure points and chafing.