A tutu is the skirt a female ballet dancer wears. It is made of many layers of stiff net, so it does not hang down like a normal skirt — it holds its own shape. There are two main kinds. The short one sticks straight out from the hips like a plate or a flower, and you see it in dances where the dancer must show fast, sharp leg work. The longer one falls to somewhere between the knee and the ankle and floats softly; you see it in the ghostly, dreamy dances. Both are called a tutu. Outside ballet, the word gets used for any short, puffy net skirt — little girls wear them to parties, runners wear them in charity races for fun, and people wear them to costume parties. When a grown man wears one as a joke, that is a very common English joke image, so the word can sound funny on its own. Note that a tutu is only the skirt. The tight top part the dancer wears is a leotard or a bodice, and the whole thing together is a costume. Countable: one tutu, two tutus.