A "traditional crib" refers to a classic or standard crib that has been around for a long time. It is a bed specifically designed for infants and is often made of wood. Full definition
And why are there so many concerns about traditional crib mattresses? (greenbabyguide.com)
It is safer than traditional crib sheets because it always stays in place — no need to worry about it coming off while baby is sleeping! (blog.guguguru.com)