DFN
The <dfn> tag stands for the "definition element", and it specifies a term that is going to be defined within the content.
The nearest parent of the <dfn> tag must also contain the definition/explanation for the term.
The <map> tag is used to define an image map. An image map is an image with clickable areas.
The required name attribute of the <map> element is associated with the <img>'s usemap attribute and creates a relationship between the image and the map.
The <map> element contains a number of <area> elements, that defines the clickable areas in the image map.
The <noscript> tag defines an alternate content to be displayed to users that have disabled scripts in their browser or have a browser that doesn't support script.
The <noscript> element can be used in both <head> and <body>. When used inside <head>, the <noscript> element could only contain <link>, <style>, and <meta> elements.