Little Miss Muffet is a character from a nursery rhyme that first appeared in print in Songs for the Nursery in 1805. The rhyme goes as follows:

Little Miss Muffet Sat on a tuffet, Eating her curds and whey; There came a big spider, Who sat down beside her And frightened Miss Muffet away.

The word "tuffet" in the rhyme probably originally referred to a grassy hillock, small knoll, or a rounded clump of grass that might make a comfortable seat for Miss Muffet. However, the word is now sometimes used to mean a type of low seat, like a footstool with no feet. Modern tuffets are padded balls, flattened at the top and bottom to make a comfortable seat.

In summary, a tuffet is a type of seat that can refer to a grassy hillock, small knoll, or a low stool. In the context of the nursery rhyme, it is likely that Miss Muffet was sitting on a grassy mound or a rounded clump of grass.