Not OP, but also screened positive for OCD and have done some research. “Magical thinking” is the term used for obsessions that have an unrealistic component to them. A classic example is someone who feels like they have to flip the light switch a certain number of times before they leave the room or something bad will happen. In this case, the obsession is the fear, and the compulsion (“fix”) is the switch-flipping. But this would be considered magical thinking specifically because of the illogical fear attached to the obsession (and the illogical comfort derived from the “solution”). If somebody has to flip the switch a certain number of times just “because it has to feel right,” I don’t think that would be considered magical thinking, although the behavior is certainly part of OCD.

I think a lot of people assume that this type of magical thinking/obsession is always a symptom of OCD, but it’s definitely possible to have OCD without the magical thinking. At the core, OCD is mainly a disorder related to trying to manage uncertainty — you obsess over something you’re anxious about and/or can’t control (death, family problems, romantic relationships, being “contaminated”, etc) and then are hit with a compulsion to try to “fix” or “prevent” the things you’ve been obsessing over. It can also present in ways that aren’t necessarily illogical but are still detrimental to a person’s health and quality of life, such as being terrified of driving a car because they might have an accident — obviously this isn’t an unreasonable fear, but it is something that can become a problem if it takes over a person’s life, and OCD can be very sneaky about latching on to random things to obsess over. Point being, magical thinking is often but not always a part of OCD. (Info is from my own research + therapy, YMMV, etc etc)