Sree Sankar
The English meaning of semantic is - related to the meaning of words!
here also it related to the meaning of HTML tags!
if we say <div> tag; that only means some section or division of the webpage. the reality is a web page contains numerous amounts of "div". So, people expect the respect developer, simply can't recognize the particular "div" by its tag name. so that we use semantic HTML tags instead of the parent "div". Child of those semantic HTML tags will be normal other tags (div, p and etc..).
Consider the below image as a webpage, then we use semantic HTML like this
these are some semantic HTML tags
