What does the medical symbol 2 with degree sign mean?

due to -

In note-taking, the Words "due to" more easily convey the meaning of "secondary".

I have read this meaning several times and each time felt as if I had not found the correct answer. Now, in consideration, I understand that if a condition is secondary, than it must be due to a more primary condition. So, secondary is technical jargon, probably said by Doctors.

Due to, is how it is said reading class notes.