Rankings in SEO refers to a website's position in the search engine results page. There are various ranking factors that influence whether a website appears.
SEO is a marketing discipline focused on growing visibility in organic (non-paid) search engine results. SEO encompasses both the technical and creative elements required to improve rankings, drive traffic, and increase awareness in search engines.
SEO rating is how higher your website or page is ranked on google search engine result page. Higher rating means a higher prefer ability to your page by the search engine during its search and thus a higher traffic for your website.