In broad terms, therapy is an attempt to heal or relieve a diagnosed condition. People with cancer undergo chemotherapy and radiation therapy. Someone who goes to a spa might be looking for help via massage therapy.
In mental health more specifically, therapy means attempts to solve psychological problems through psychological means. This means that while pharmacotherapy is an emerging modality for addiction and mental health, the use of medications doesn’t fit into the modern discussion of what therapy is for people who have mental health conditions.
In the mental health space, if you’re seeking therapy, you’re typically going someplace where at least one trained professional can provide treatment. Sometimes, this is as simple as talking through your situation, and sometimes, it’s more complicated.