The term "Autism Spectrum" refers to a range of conditions that are characterized by challenges with social interaction, communication, and repetitive behaviors. These conditions include Autistic Disorder, Asperger's Syndrome, Rett Syndrome, Childhood Disintegrative Disorder, and Pervasive Developmental Disorder Not Otherwise Specified (PDD-NOS). The term "spectrum" refers to the fact that these conditions can vary widely in terms of their severity and symptoms. Some individuals with autism may have mild difficulties while others may experience more significant challenges. Additionally, some people with autism may be highly skilled in certain areas such as music or math, while experiencing difficulty with social interactions. The term "autism spectrum" is used to describe the range of these conditions and their varying degrees of severity.