You want to know what is a Tag?
Tags are KEYWORDS that allow others to FIND YOUR SITE….. using TAGS with a great TITLE and CONTENT will allow search engines to verify your Post as a “relevant”, “worthy” Post.
Line up the TITLE, BODY CONTENT, CATEGORIES and TAGS and you may just be found….
What TAGS did you use to write this POST? Example – “what is a tag”, “what is a tag in wordpress”.