Definition - What does Stainless Steel mean?
Stainless steel is a generic term for a type of alloy that belongs to the corrosion resistant family of alloys that contain 10.5% or more chromium by mass. The chromium present in stainless steel forms a passive layer, which is a chromium-rich oxide film that prevents stainless steel from corroding.
Stainless steel is an alloy of iron, which is why it may also be known as inox steel or inox.
Corrosionpedia explains Stainless Steel
The chromium-rich oxide layer is a passive layer that forms automatically on the surface of stainless steel due to the presence of chromium within it. This layer is invisible and adheres to the stainless steel, making it highly resistant to corrosive media. Increasing the amount of chromium in the stainless steel imparts high corrosion resistivity and thus makes stainless steel a superior metal. The film is rapidly self-repairing in the presence of oxygen, and damage by abrasion, cutting or machining is quickly repaired.
Ordinary steel readily corrodes, rusts and stains when it comes in contact with water or any other corrosive media. However, stainless steel does not corrode unless it is put into a low oxygen, high salinity and poor air circulation environment.