What I think the title Means

I think that the title is The Absolutely True Diary of a Part-Time Indian because he goes to an Indian school, is half Indian, and he learns that they treated the Indians badly. The teacher ends up having a one on one talk with Junior and he prefers him to go to Reardan High because Junior is different than the others. I also think that it says Part-Time Indian because the first school he went to was full on Indians and the school he's going to now is completely opposite.