What is the Meta tag or Meta keyword and its limit?

Although technically meta descriptions can be any length, Google often truncates snippets to between 155 and 160 characters. We advise keeping meta descriptions between 50 and 160 characters long in order to ensure that they are appropriately descriptive.

A special kind of meta tag called a "meta keyword" can be found in the HTML code of a web page and helps search engines understand the subject of the page.