Subependymoma is a rare type of brain tumor that is mostly benign. However, it can still cause significant neurological damage due to its location and size. The term "subependymoma" is a medical term used to describe a specific type of tumor. However, there are several synonyms that can be used to describe the same tumor. These synonyms include subependymal glial tumor, subependymal astrocytoma, subependymal giant cell astrocytoma, and subependymal tumor. These terms are often used interchangeably with subependymoma and refer to the same type of tumor, which is commonly found in the wall of the brain ventricles.