What is this "grid" called?

Hi everyone,

I'm building a website with the Wix platform. So you know I'm far from an expert in web development.

What's the 'grid' called in the attached photo?
Photo: https://imgur.com/a/Q25TRtG

I want to make a similar custom grid in Wix and add a "show more" button that shows additional 'articles' with content. You can add code in Wix. It shouldn't be that hard I just don't know where to look to find out more about this.

Any help is appreciated.