My :twocents:
Etymologically, the term “doctrine” means this:*late 14c., from Old French doctrine (12c.) “teaching, doctrine,” and directly from Latin doctrina “teaching, body of teachings, learning,” from doctor “teacher”*So really, anything that is a “teaching” is a doctrine. It’s something that is “taught.” As David says, we should give the assent of faith to all doctrines taught by the Church.
A dogma is also a doctrine. The difference is that a dogma is recognized with the highest certification of the Church. There is no degree of uncertainty in a dogma.
For example, that Jesus was fully God is a dogma. It is certain. We must give our assent to that teaching absolutely.
That we each have one guardian angel is a doctrine. This is a common teaching in Church history and we should give our assent to that teaching, even if the Church has not made a dogmatic pronouncement on the matter.