Why not reuse legend
From WHATWG Wiki
Tables and figures should have captions, or at least legends.
Lists sometimes need headers.
The dt element is sometimes a mini-header.
label can be viewed as a mini-header.
Why are there so many similar elements, and why are they not being re-used?
Unfortunately, each of the existing elements has some behavior (in practice, at least) that causes technical problems when trying to reuse them.
