I only know purling as a knitting term (I don’t know what it means as I tried to learn how to knit over lockdown and found it too stressful).As nouns the difference between purlin and purling is that purlin is a longitudinal structural member two or more rafters of a roof while purling is...wikidiff.com
I've never been a roofer, but I have built things. Apparently no one I've ever worked with knew the correct term "Purlin" either. No one, ever. That's quite troubling in retrospect.
Did any of yee know that it's not called a purling?