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Synonyms

on the dot

Idioms  
  1. Exactly on time, as in We had to be there at eight on the dot. The dot in this idiom is the mark appearing on the face of a watch or clock indicating the time in question. It may come from the earlier to a dot, meaning “exactly” since the early 1700s but no longer heard today. [c. 1900] Also see on the button.