pompom       
noun [ C ] (also pom-pom, pom pom); (US also pompon) uk/ˈpɒm.pɒm/ us/ˈpɑːm.pɑːm/
 (尤指帽顶上装饰用的)绒球,丝球
a small ball of wool or other material used as a decoration, especially on the top of a hat
  I had a white sweater and a maroon hat with a white pompom.
 We admired the sentries at the temple, who wore ballet skirts with great pompons on their shoes.
 - More examples
 - Tidy up your pompom by trimming off any uneven lengths of wool.
 - Someone hung three gold string necklaces with pom-poms round his neck.
 - Continue marching and shake both pompoms together above your head, counting to eight as you step.