Sīla is often translated as virtue.
A virtue is a trait, quality, that is deemed morally good. Now would you consider right concentration to be a virtue? Or right effort? And what about right view? I do, yet those are not sīla.
And what to think of bad virtue... A bad quality which is deemed morally good? This is rather strange right? Yet sīla can be good or bad.
Good or bad speech, good or bad doing, good or bad way of life, those are sīla. Which to me stands for conduct.
Sīla (nt.) conduct.