sash [L16th] A sash is now worn over one shoulder or around the waist, but it was originally wrapped round the head. Between the late 16th and early 18th centuries a sash was a length of fine fabric twisted round the head as a turban, as in some Middle Eastern countries—the word is from Arabic. The sash in sash window [L17th] is an alteration of chassis, which means ‘frame’ in French, based on Latin capsa ‘box’. Originally both French and English people pronounced the final -s of chassis. English-speakers then took this as a plural form and shortened it to form a new singular which became sash. Chassis was readopted from French in the early 20th century to mean ‘the base frame of a vehicle’. See also scarf.