The train departed at exactly 9 o'clock.
The meeting started at exactly 3 o'clock.
合計は１万円ジャストだった。
The total was exactly 10,000 yen.
お会計は1000円ジャストです。
The bill comes to exactly 1000 yen.
just an idea; just a thought
internal clock that is always correct
perfect fit
Borrowed from English 'just'.