The term 'Tender of Nursery Rhyme Sheep' refers to the character Little Bo Peep from the popular nursery rhyme. Little Bo Peep is a shepherdess who loses her sheep and is unable to find them. She is often depicted as a young girl wearing a bonnet and carrying a crook. The nursery rhyme is believed to have originated in the 18th century and has been adapted into various forms of media, including books, films, and television shows.