A float is like a big wagon pulled by horses. It's usually used to carry heavy things, like big piles of hay or big barrels of water. The horses are attached to the float with a special harness so they can pull it along. It's kind of like when Mommy or Daddy takes you for a ride in a wagon, but much bigger and stronger horses pull it. People used to use floats more often in the past because they didn't have cars and trucks to transport things. Today, some people still use floats for special events or parades.