Stainless means resistant to staining, rusting, or corroding. When something is stainless, it stays clean and shiny even when exposed to water, air, or food.

The most common use is stainless steel, a type of metal alloy that contains chromium, which helps prevent rust. Regular steel can turn orange and flaky when it gets wet, but stainless steel stays smooth and silver. That's why kitchens are full of stainless steel: sinks, refrigerators, cooking pots, and utensils. Surgeons use stainless steel tools because they can be cleaned thoroughly without rusting. Builders use stainless steel for outdoor railings and sculptures that need to withstand rain and snow for decades.

You might see the word used more broadly to describe a reputation that remains clean and unblemished, though this usage is less common. But mostly, when you hear stainless, someone's talking about that gleaming, rust-proof metal that keeps its shine year after year.