There is no single definition of Special Education, some of them are mentioned below.  Thus, Special Education is:
• educational programs for students whose mental or physical ability, emotional functioning, etc. require special teaching approaches, equipment, or care within or outside a regular classroom
• programs designed to meet special learning needs of students
• also known as special ed or additional support needs, teaching that is modified or individualized maintenance to students with exceptional needs or disabilities
• specially designed instruction to meet the unique needs of students with disabilities
• education, often in separate special schools, for children with specific physical or mental problems or disabilities
• education of physically or mentally disabled children whose needs cannot be met in a mainstream classroom (the Random House Webster's Unabridged Dictionary defines special education as an education that is modified or particularized for those having singular needs or disabilities)

Special education covers education for students, which are in want of additional support so as to succeed in studies. It also pertains to education for those students unable to compete in a regular classroom conditions. Since in the United States every child has the right to get an education, irrespective of the intellectual faculties one can receive school education and master basic skills.
For students who are not fitted to a mainstream course some special education services providing separate classrooms. Occasionally, special education services may facilitate children with a particular problem. For instance, children with speech defects may run a speech therapy, and special occupational therapy might be prescribed for students with physical problems. This is common practice in grammar schools on the basis of pull out. Such students will be called out of the classroom to exercise needed procedures, in all other respects they will attend ordinary lessons.

Now and then student with permanent problems like autism could be provided with a special aide in the classroom so that to study on equal terms. Special education doesn’t mean that a child has reduced mental faculties, this is not necessarily so. Fairly often very intelligent students receive services to facilitate their accommodation to the school settings.
Children of preschool age may also receive special education services. Those parents worried about speech, physical delays, or major health problems of their child, may appeal to the Special Education Local Plan Area program as soon as their kid is three if they’re interested in that. According to state and federal law, SELPA must pursue research for those students who prove to be at risk for developmental lag or those with a worsened state of health.