Noah Webster's Dictionary (n.) The uppermost cover of a bed or of any piece of furniture.

Multi-Version Concordance Coverlet (3 Occurrences) Judges 4:18 and Jael goeth out to meet Sisera, and saith unto him, 'Turn aside, my lord, turn aside unto me, fear not;' and he turneth aside unto her, into the tent, and she covereth him with a coverlet. (YLT) 1 Samuel 19:13 And Michal took the image, and laid it in the bed, and put the net of goats' hair at its head, and covered it with the coverlet. (DBY) 2 Kings 8:15 And it came to pass on the morrow, that he took the coverlet, and dipped it in water, and spread it on his face, so that he died: and Hazael reigned in his stead. (ASV DBY JPS RSV)