Code that has been superseded by more efficient or accessible alternatives is described as deprecated.
The World Wide Web Consortium (W3C) reviews and approves additions to the HTML standard (among others). At the same time as new revisions are released, earlier code elements may be formally ‘frowned-upon‘ (deprecated).
An example of a commonly-used element that has been deprecated with the introduction of HTML standard 4.0 is the font element (used to set HTML text size);
<font size="2">sample</font> (RIP)
The W3C recommendation is to use stylesheets, rather than the font element, to set text size.