Wavy hair is commonly considered to be a looser version of curly hair. They usually sit between straight hair and curly/coily hair.
Wavy hair is characterized by S-shaped loose curls, and in the curly hair community, they are referred to as Type 2 hair.
Within the wavy hair category, there are three other subcategories, namely Type 2A, Type 2B, and Type 2C hair.