I am doing a keyword research for my new website and I was wondering if as far as search engines concerned there is any keyword rank difference between connected and separated words. For example is it better to use ?dog collars? or ?dogcollars? for my targeted keywords? After analyzing both keywords I got the following results: ?dogcollars? has 450,000 searches and 10,500 competition, while dog collars has 301,000 searches and 2,300,000 competition. Obviously it looks like ?dogcollars? is by far better choice, however does it mean that all the meta tags should be tuned to ?dogcollars?? Should H1 Tag and page text include ?dogcollars?? or search engines interpret both ?dogcollars? and ?dog collars? as the same keyword? I ran a search on ?dogcollars? and looked on all the Google?s 1?st page sites, and no-one was using ?dogcollars? neither in meta tags or text ? all of them used ?dog collars?. How to explain it?