BEST definition: 1. of the highest quality, or being the most suitable, pleasing, or effective type of thing or…. Learn more. Someone's best is the greatest effort or highest achievement or standard that they are capable of. Miss Blockey was at her best when she played the piano. One needs to be a first-class driver to get the best out of that sort of machinery. Cruise ships are perhaps best known for amenities like buffets and swimming pools, but their medical facilities also have the capability to treat a wide range of illnesses and injuries, from common colds to heart attacks. Use the Best Buy store locator to find stores in your area. Then, visit each Best Buy store's page to see store hours, directions, news, events and more. Shop Best Buy for electronics, computers, appliances, cell phones, video games & more new tech. Store pickup & free 2-day shipping on thousands of items. BEST definition: of the highest quality, excellence, or standing. See examples of best used in a sentence. Nothing is better than the best — this is a word for the absolute number one example of something. Best is the opposite of worst. Idioms (all) for the best, producing good as the final result: It turned out to be all for the best when I didn't get that job. Idioms as best one can, in the best way possible: As best I can tell, we're the first ones here. Someone's best is the greatest effort or highest achievement or standard that they are capable of. Miss Blockey was at her best when she played the piano. 1. In a most excellent way; most creditably or advantageously. 2. To the greatest degree or extent; most: He was certainly the best hated man in the ship (W. Somerset Maugham).