Mynocks have 1. I can't find the explanation of what it defends from. Page, please?
What is M/R defense?
Melee and Ranged.
Melee and Ranged Defense. I'm away from my book, but each rank of Defense grants 1 Setback to attacks against that character.
It doesn't stack with other sources such as cover, so if a character with a M/R Defense of 1 hides behind a wooden crate (which provides cover of 1 Setback), the character still only has 1 Defense providing 1 Setback against attacks.
Defense is explained on pages 206 and 207 of the CRB.