In simple terms, these are the search words / phrases used by people in search engines to find content about a business, activity, person etc. If these keywords find best match on your website pages, your website will feature high on search engine page.
CAUTION: STUFFING YOUR WEBSITE/WEBPAGE WITH IRRELEVANT KEYWORDS CAN HAVE YOUR WEBSITE BLACKLISTED AND BARRED IN SEARCH ENGINES.
You may also like one or more of the following options:
Search Engine Marketing (SEM)