What's the actual difference between a therapist, a psychologist, and a psychiatrist?

Trying to figure out who I actually need to talk to. These terms get used interchangeably but I assume they're not the same thing.

"Therapist" is a broad umbrella term that can include several different licenses (like licensed clinical social workers, licensed professional counselors, or marriage and family therapists) who provide talk therapy but generally can't prescribe medication. A psychologist typically holds a doctoral degree (PhD or PsyD), can provide therapy and psychological testing/assessment, but in most places also cannot prescribe medication. A psychiatrist is a medical doctor (MD or DO) who specializes in mental health and can prescribe and manage medication, though many psychiatrists today focus mainly on medication management rather than ongoing talk therapy, often working alongside a separate therapist. A common and effective setup for someone dealing with something like depression or anxiety is a therapist for regular talk therapy plus a psychiatrist (or sometimes a primary care doctor) specifically for medication, if medication is part of the plan — they don't have to be the same person.