The process of optimizing a website for Google search engine is called Google SEO. Google is the giant search engine that has been always far ahead of its other competitors in the internet search market.
About 75% of internet users use Google for their search requirements. Search results on Google are more accurate than any other SE.
Google constantly refines its search algorithm and has a very good reputation on penalizing those intentionally tried to spam its search results and has done a great job in terms of relevancy and speed of search.
Ranking well on Google also will results in good ranking on Bing, Yahoo! or any other major search engine but the other way around is not always true.