In the current multicol Working Draft the element that has column-count or column-width applied is referred to as the multicol element. In the discussions at TPAC @fantasai noted there is some confusion around what we call this element.

I noted that people were often referring to it as the multicol container in the meeting, which matches how we talk about flex and grid containers.

The current definition is here.

It seems that it would make sense to describe the multicol element/container in the same way as flex and grid, raising this issue for discussion of that.