# Attribute

Metadata attached to C# declarations for compilers, tools, or runtime code.

## What is **Attribute** in C#?

**Attribute** — Metadata attached to C# declarations for compilers, tools, or runtime code.

```csharp
class Checkout
{
    [Obsolete]
    void OldCheckout()
    {
    }
}
```

Level: Master · [More C# terms at this level](https://www.ask-codey.com/glossary/subjects/c-sharp/master)

Updated: September 27, 2026

## In other subjects

- [Attribute in Database](https://www.ask-codey.com/glossary/attribute-database)
- [Attribute in HTML](https://www.ask-codey.com/glossary/attribute-html)

Source: https://www.ask-codey.com/glossary/attribute-c-sharp