Organic Traffic is that traffic, where you don't have to make a backlink for it. Search engine automatically boost that website and having a traffic on it.
CSS or Cascading Style Sheet languages used to define visual appearance and formatting of HTML documents. WordPress themes use CSS and HTML to output the data generated by WordPress. CSS is very simple to use and easy to learn.
The bounce rate is a measure used by google for website analytics to determine the validity and relevance in the subject space which your website resides.
Webmaster tool is a SEO tool, where you can see your website traffic, internal link, sitemap, error on your site, broken link and many things you can check through webmaster tool.
White Hat SEO follow the tearms, conditions, rules and policies of search engines. White Hat SEO is more frequently used by those who intend to make a long-term investment on their website.
Database Management System is the software system that allows users to define, create and maintain a database and provides controlled access to the data.
Robot.txt is a text file, you can write in notepad and word pad with robot.txt extension. If you don't want to crawl your file or folder you just put the Robot in it. So search engine doesn't going to crawl that file or folder.