# Block formatting context

An area where blocks stack; a new one contains floats.

## What is a **block formatting context**?

A **block formatting context** is an area where blocks stack top to bottom. A new one contains its floats and stops margins collapsing through it.

```css
.media-object { display: flow-root; }   /* new context: wraps its floated image */
```

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

Updated: September 27, 2026

Source: https://www.ask-codey.com/glossary/block-formatting-context