Your child or students may be receiving special education services.
I want to emphasize:
Special education is a service. Special education does not refer to a place, and it does not refer to a person.
These services may be offered in a variety of settings ranging from the least restrictive, in the general education classroom, to more restrictive, such as a separate classroom. Some students flourish in a more restrictive environment, and some students flourish in a less restrictive environment; it is highly individualized.
As a rule:
The environment should best meet the needs of the student in the least restrictive environment (LRE).