what is meta tag

[niu_noida]

what is meta tag.  why meta tag is importance on sites....??

[Buffer Overflow]

It's hidden data that doesn't show in the internet browser. Search engine bots use them to help index your site.
Meta data was abused years ago to obtain higher search engine rankings, so they aren't very important now.

Whilst technically not a meta tag, the <title> tag is important so you should still use that one. Also the "<META NAME="Description" CONTENT="Your descriptive sentence or two goes here.">" one is still used so use that one as well.

At the end of the day don't worry too much about them. Concentrate on designing a good website with good content. Backlinks will come naturally if your website is good.