Final answer:
The Lord's wife gives Sir Gawain a sash, which is also known as a girdle believed to protect him from the Green Knight.
Step-by-step explanation:
The Lord's wife gives Sir Gawain a sash on the last day. This occurs in the story of Sir Gawain and the Green Knight, which is a chivalric romance from the 14th-century Middle English literature. This sash, also often referred to as a girdle, is said to possess magical properties that have the power to protect Sir Gawain from harm. The wife of the lord, Lady Bertilak, offers Gawain the sash with the understanding that it would keep him safe from the fatal blow of the Green Knight, which is a crucial plot element in the story. Sir Gawain accepts the sash, and it becomes a symbol of his survival and the complexity of his honor and chivalry.