SEO stands for Search Engine Optimization. It’s an important part of any website that helps search engines understand how to index your content so people can find it when they search online. . Some of the popular search engines are Google, Bing, Yahoo etc.
Search Engine Optimization metrics provide insights on website health, growth in users traffic, source of new users acquisition and their activities on the site.
The impression count indicates the number of time website (a particular web page) has appear in search results for keywords related to your services and offerings. The corresponding metric to impression is CTR i.e. Click Through Rate. CTR indicates after viewing your web page in the search result (impression), how many users click and visited your site. The impression and CTR data can be viewed in Google Search Console.
Website visitors (users) who found your website in internet search. It's also important to know if you have acquire users by running a paid advertisement, it doesn't add up in organic traffic. This data is available in Google Analytics.
Keywords are a starting point to start the SEO activities. Many companies struggle to decide on the top keywords to rank for their site. The easy way out is to refer the existing web pages or services offered by the company as 'Seed Keywords". After a month or two, one should review and if require change the primary keywords.
The bounce rate percentage indicates the number of website visitors (users) who had exited the website after viewing one page (the landing page). The ideal situation is to have lower bounce rate percentage. One of the way to reduce bounce rate is to increase the inside page navigation - buttons and hyperlinks within the web page that encourage users to move from one page to another in search of quality content.
The number indicates on an average the number of minutes each users spend on the site. One should aim for a higher number, as indicates that users is finding the information relevant or useful.
Page loading speed is a critical metrics to track. Considering the low attention span of today's internet users, it is necessary that website loads faster. Anything in the range of 5 seconds to 10 seconds can be consider as an ideal page loading time.
DA i.e. Domain Authority score indicates the popularity of your website in search engine ranking. Higher number indicates that search engine will drive more traffic to your site for related search query. Another associated concept is PA (Page Authority).
The number of website / web pages that has your website details.Read More : Comprehensive SEO beginner's Guide