Know What is SEO...?

SEO: Stands for "Search Engine Optimization". It is the way of Improving or Optimizing a website to rank better in Search Engines for driving high Traffic. 

Many sites  have defined SEO in their own ways, Some of them are: 

Search engine optimization (SEO) is the process of improving the visibility of a website or a web page in a search engine's "natural" or un-paid ("organic") search results. -(Wikipedia)

SEO is a technique which helps search engines find and rank your site higher than the millions of other sites in response to a search query. SEO thus helps you get traffic from search engines. -(Webconfs).

Search Engine Optimization is the process of improving the visibility of a website on organic ("natural" or un-paid) search engine result pages (SERPs), by incorporating search engine friendly elements into a website. -(whatisseo)

Search engine optimization is a methodology of strategies, techniques and tactics used to increase the amount of visitors to a website by obtaining a high-ranking placement in the search results page of a search engine (SERP) -- including Google, Bing, Yahoo and other search engines. -(webopedia)

The way you build your website so that search engines gobble the pages up and show them to visitors ahead of your competition.-(Envoc)