Hey Perfectly_Imperfect,

I just bumped up a thread in Psychotherapy that should answer your question but simply (as it is in Canada, might be different elsewhere):

Psychiatrist is a medical doctor with a specialization in psychiatry. Can do "therapy" sessions, but mostly just specializes in prescribing meds.

Psychologist is a person with a PhD in psychology. Does research, therapy, and in Canada can't prescribe meds (I don't believe so anyways).

Therapist - different degrees depending on the individual, but anyone who "counsels" people on their problems.

(If I've gotten this wrong, I'm sorry! It's late/early and my brain is fried)