list is a basic LaTeX environment used to create list environments of all kinds, including
enumerate and the
description environments, as well as the 'trivial' list environments used for such things as quotations and abstracts.
You don't usually use the
list environment directly in documents. Instead, it is used to create higher level environments, such as
itemize, for use in documents.
Before packages such as
enumitem were available, custom
enumerate environments were created in this way. (Of course, they still can be, but
enumitem makes it unnecessary in most cases.)
Here's an example specifying a simple variant on the
\item[Question] some of what?