Posted by Henry on November 23, 2004
In Reply to: On the dot posted by ESC on November 21, 2004
: : I know it means exactly
: : but where did the phrase originally come from?
: "The expression is probably a reference to the minute hand of the clock being exactly over the dot marking the given minute on the dial." From "Brewer's Dictionary of Phrase and Fable" revised by Adrian Room (HarperCollinsPublishers, New York, 1999, Sixteenth Edition).
A similar phrase is 'on the stroke of (nine)', meaning as the clock strikes (nine) o'clock.