The 1700's smiths didn't have to worry about it because they didn't have Stainless steel, Powdered metal technology alloys, or any other alloy steels.
As for definitions, this is the knife section, so its natural to assume its about blade steels, if not post is in general. Blade steels requirements can vary so much its almost a requirement to state what steel is being used in order to get any meaningful information in the first place :D