> Historically, the nominal dimensions were the size of the green (not dried), rough (unfinished) boards that eventually became smaller finished lumber through

> Historically, the nominal dimensions were the size of the green (not dried), rough (unfinished) boards that eventually became smaller finished lumber through drying and planing (to smooth the wood). Today, the standards specify the final finished dimensions and the mill cuts the logs to whatever size it needs to achieve those final dimensions. I was originally pointing out that the naming is simply a standard and convention, 'dimensional lumber'. All that matters is that if I buy a '2 by' almost anywhere in the United States, it will be close to the same size and characteristics.