Data descriptor
ASC Collections Data Dictionary (Beta v1.3)

Describes the process of change for young people with disabilities as they move from childhood to adulthood. This period may involve additional interdisciplinary work and planning between involved agencies (for example: collaboration may occur between a children's social care service and an adult social care service within some CASSRs).
Definition
NICE Guideline NG43 - Transition from children's to adults' services for young people using health or social care services

The process of moving from children's to adults' services. It refers to the full process including initial planning, the actual transfer between services, and support throughout.
Plain English definition
Think Local Act Personal (TLAP) Jargon Buster

The process by which young people with health or social care needs move from children's services to adult services. It should be carefully planned, so that there are no gaps in the care young people receive. Young people and their families should be fully involved in the planning process.