I think it used to mean 'underline', then got changed because that was considered undesirable. From the link above: https://developer.mozilla.org/en-US/docs/W

I think it used to mean 'underline', then got changed because that was considered undesirable. From the link above: https://developer.mozilla.org/en-US/docs/Web/HTML/Element/u https://developer.mozilla.org/en-US/docs/Web/HTML/Element/u > You should not use <u> to simply underline text for presentation purposes, or to denote titles of books. > To underline text without implying any semantic meaning, use a <span> element with the text-decoration property set to "underline"..."