What is SEO?
Quite simply, SEO is the umbrella term for all the methods you can use to ensure the visibility of your website and its content on search engine results pages (SERPs).
The methods vary from technical practices you can achieve behind the scenes on your website (we tend to refer to this as ‘on-page SEO’) to all the promotional ’off-page’ approaches you can use to raise your site’s visibility (link-building, social media marketing).
For the purpose of this article, when we talk about visibility, we mean how high up the SERP your website appears for certain search terms in the ‘organic’ results. Organic results refer to those that appear naturally on the page, rather than in the paid-for sections…
Article source- https://searchenginewatch.com/2016/01/21/seo-basics-22-essentials-you-need-for-optimizing-your-site/