Meaning/Usage: The exact time(準時;指定時間)
Explanation: A dot is seen as a very small target. It is like hitting the very center of a dart board or the bulls-eye. When it refers to time, it means exactly that time not a minute after or before.
"I don't want to be waiting for you, so you'd better be there at three o'clock on the dot."
"He's supposed to show up at four on the dot. If he is late even a minute, I'm taking off."
"You'd better be here by 1:30, because we're leaving at two o'clock on the dot."
A: "We have to go to Los Angeles tomorrow. What time should we meet?"
B: "We have to be at the airport at 4:00 o'clock, so let's meet at two o'clock on the dot."
Other Common Sentences
"Meet me at the bus station at six o'clock sharp."
"Let's meet at the book store exactly at 1:00."