You can see from the Google AdWords Keyword Planner screenshot above the highest monthly traffic keywords are Shopping/Shop, not Store.
Targeting “Shopping” highest priority followed by “Shop”, followed by “Store”, since all three are considered synonyms by Google targeting one (Shopping) in the title tag and the synonyms (Shop and Store) in the content and backlinks (via the anchor text of backlinks) could achieve high rankings for all three keywords and their derivatives.
Continue Reading SEO Analysis of the Amazon USA Website Title Tag