When I do inner-child work in therapy my T always referes to that as a "Part" of me. Or like when you are trying to explain something to someone...do you ever use the phrase "well, part of me feels this way or part of me feels that way" For me, I can respond in many different ways to the same situation and those are different "parts" of me. Like I can respond childishly or very adult like. I think that goes hand in hand with regression in therapy. There was a post here awhile back that asked something about your real age vs the age you are in therapy. So, like, if you walk into T's office and suddenly you feel like your 6 or 12 or however old-I believe that is a "part" of you. But that's just my opinion and how it goes for me with my therapy, everyone is different. hope this helps.