"Jack and Jill" is a traditional nursery rhyme that tells the story of two characters, Jack and Jill, who go up a hill to fetch a pail of water. The rhyme describes their journey and the mishap that occurs when Jack falls down and injures himself, followed by Jill who also falls while trying to help him. The rhyme is often recited to children and is known for its simple rhythm and repetitive structure. It has been passed down through generations and is commonly used in early childhood education to teach language and rhythm.