> For the complete documentation index, see [llms.txt](https://nxp.gitbook.io/mr-b3rb/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://nxp.gitbook.io/mr-b3rb/introduction/nomenclature-used-on-the-b3rb.md).

# Nomenclature used on the B3RB

## Upper and Lower Chassis

Here we distinguish between the B3RBs lower & upper chassis: 

<figure><img src="https://396338415-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FU93yDWZcgjXGgsC1Duqv%2Fuploads%2FRi5eaY1uGvkWihQtGSsO%2Fimage.png?alt=media&amp;token=47bdc858-4463-4be4-a960-16f9720f0a0b" alt=""><figcaption></figcaption></figure>

## Lidar Arch

This is the assembled buggy minus the top cover. The "bridge" with the lidar module may be referred to as the top plate, the top arch, Lidar arch or the lidar plate:

<figure><img src="https://396338415-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FU93yDWZcgjXGgsC1Duqv%2Fuploads%2FTuhcfWpGb6k2PURFvAGe%2Fimage.png?alt=media&amp;token=ec6a7ee9-36a3-41be-b022-50256704ab4c" alt=""><figcaption></figcaption></figure>

You will notice that throughout this guide, we use these names. At least now you know what we mean by it.&#x20;