1
general::
1. Superior to, as in He's no better than Tom at writing a memo. [9th century] 2. More than, larger in amount or greater in rate, as in My new car can do better than 100 miles an hour, or The new plan will cut better than 15 percent of costs. Some authorities consider this usage colloquial and advise that it be avoided in formal writing. [Late 1500s] Also see BETTER HALF, def. 1.
American Heritage Idioms