# Nullable Reference Type

*noun*

say it: **“NUL-uh-bul REF-er-ens type”** **/ˈnʌləbəl ˈrɛfərəns taɪp/**

A reference type written with a ?, like string?, to say that its value may be null.

## What is **Nullable Reference Type** in C#?

**Nullable Reference Type** — A reference type written with a `?`, like `string?`, to say "this may be null". The compiler then warns you wherever you use it without checking, and treats plain `string` as never null.

```csharp
string? region = null;          // fine: may be null
Console.WriteLine(region ?? "(no region)"); // (no region)
```

## In a sentence

- “Region is a **nullable reference type**, string?, because some customers have no region.”

Level: Journeyman · [More C# terms at this level](https://www.ask-codey.com/glossary?category=c-sharp&level=3)

Updated: October 28, 2026

Source: https://www.ask-codey.com/glossary/nullable-reference-type