Psychiatry - typically refers to mental health care and behavioral health care provided by physicians (i.e. MD/DOs). Aka: A psychiatrist is a DOCTOR with a medical license that can prescribe and monitor medications, or provide other interventions such as electroconvulsive therapy or IV ketamine.

Therapy - is the provision of mental health care through non-pharmacological means --- so like talk therapy like psychoanalysis, or skills building type therapy like cognitive behavioral therapy, or group therapy, etc. It's mostly person to person talking and interaction and relationship building and using that to treat mental health issues.

SO a psychiatrist CAN PROVIDE therapy and CAN BE CALLED a therapist, but not all therapists are psychiatrists. Often therapists are psychologists (PsyD or PhD in psychology) or licensed clinical social workers, etc.

Psychology is a general academic term and doesn't necessarily have to do with providing healthcare. There are plenty of psychologists (people with an academic degree in psychology) who do NOT provide therapy (*though of course there are some who do).

CAVEAT THIS IS FROM MY PERSONAL EXPERIENCE AS A PSYCHIATRIST IN AMERICA