What are keywords?
Keywords define your business, they are descriptive words to describe who you are and what you do.
When relating keywords to SEO; keywords are the terms users enter into search engines such as Google and Yahoo to find answers on the internet.
So when the keywords that you use often on your website, match the phrase a user searches for, you will appear in the SERP, resulting in traffic to your website. Therefore, investing time getting your keywords right, is essential in directing search traffic to your site.