“Parts work” is a colloquial term for therapeutic techniques that help us to look at ourselves as comprised of various parts, with slightly differing agendas, needs and desires. Internal Family System (IFS) is one such therapeutic technique. It can help to reduce the polarization and the tug-of-war between opposing parts, such as your Inner Child and your Inner Critic. To know more about IFS, click here.
Identifying parts in your psyche does not mean that you have Multiple Personality Disorder (currently known as Dissociative Identity Disorder).