Stainless steel is a type of metal alloy that contains at least 10.5% chromium, which makes it highly resistant to corrosion and staining. This means that it does not easily rust or get damaged by exposure to water, acids, alkalis, or other chemicals. The term "stainless" refers to the fact that the steel is less prone to stains than regular steel. Stainless steel is commonly used in various applications such as cutlery, kitchen appliances, and construction materials due to its durability and ease of maintenance.