According to Merriam-Webster's Collegiate Dictionary, the tenth addition, transition is “the passage from one state, stage, subject, or place to another.”  Therefore, when we consider the word by itself, it represents change.

Transition was defined by the Council for Exceptional Children's Division on Career Development and Transition in 1994 as:

Transition refers to a change in status from behaving primarily as a student to assuming emergent adult roles in the community.  These roles include employment, participating in post secondary education, maintaining a home, becoming appropriately involved in the community, and experiencing satisfactory personal and social relationships.  The process of enhancing transition involves the participation and coordination of school programs, adult agency services and natural supports within the community. The foundation for transition should be laid during the elementary and middle school years, guided by the broad concept of career development.  Transition planning should begin no later than age 14, and students should be encouraged, to the full extent of their capabilities, to assume a maximum amount of responsibility for such planning.  (Halpern, 1994, p.116)

§300.1 Purposes

1. To ensure that all children with disabilities have available to them a free appropriate public education that emphasizes special education and related services designed to meet their unique needs and prepare them for further education, employment, and independent living.

…in addition 

§300.43 Transition Services

1. Transition services means a coordinated set of activities for a child with a disability that
1. is designed to be within a results-oriented process that is focused on improving the academic and functional achievement of the child with a disability to facilitate the child's movement from school to post-school activities, including post secondary education, vocational education, integrated employment (including supported employment), continuing and adult education, adult services, independent living, or community participation;
2. Is based on the individual child's needs, taking into account the child's strengths, preferences, and interests; and includes
   1. Instruction;
   2. Related services;
   3. Community experiences;
   4. The development of employment and other post-school adult living objectives; and
   5. If appropriate, acquisitions of daily living skills and provision of a functional vocational evaluation

§300.320 Transition services.

(b) Transition services. Beginning not later than the first IEP to be in affect when the child turns 16, or younger if determined appropriate by the IEP Team, and updated annually, there after, the IEP must include

(1) Appropriate measurable post-secondary goals based upon age appropriate transition assessments related to training, education, employment, and where appropriate, independent living skills; and

(2) The transition services (including courses of study) needed to assist the child in reaching those goals.

(c) Transfer of rights at age of majority. Beginning not later than one year before the child reaches the age of majority under State law, the IEP must include a statement that the child has been informed of the child's rights under Part B of the Act, if any, that will transfer to the child on reaching the age of majority under §300.520

§300.321(b) Transition services participants

(1) In accordance with paragraph (a)(7) of this section, the public agency must invite a child with a disability to attend the child's IEP Team meeting if a purpose of the meeting will be the consideration of the post-secondary goals for the child and the transition services needed to assist the child in reaching those goals under §300.320(b).

(2) If the child does not attend the IEP Team meeting, the public agency must take other steps to ensure the child's preferences and interests are considered.

(3) To the extent appropriate, with the consent of the parents or a child who has reached the age of majority, in implementing the requirements of paragraph (b)(1) of this section, the public agency must invite a representative of any participating agency that is likely to be responsible for providing or paying for transition services.