Search Engine Optimisation
All the major search engine for example Google, Bing, Yahoo comes up with their standard results in the form of Web pages, Images, Videos etc. These results are shown by Search Engine on the behalf of relevancy of user to what is searched. This whole process is termed as Search Engine Optimisation.
Tools for SEO
It is very genuine to say there is no such a term SEO without keywords. Generally, keywords are the reason to for search engine to redirect the relevance Audience to your content. There are some effective ways to plan needy keywords for your page, Google adwords do it very well. Although, keyword planning is good, but keep in mind about the limits of it.