How is “on the dot” used?

In The Life and Death of Colonel Blimp (1943), one line is: “At midnight on the dot, it's got to be closed,”

Which movie is “on the dot” from?

The clip at the top of this page is from The Life and Death of Colonel Blimp (1943).

At midnight on the dot, it's got to be closed,

8 作品で登場 · 1 本目

exactly on time or at the exact time mentioned

くだけた · 8 本の映画に登場

オックスフォード映画の 100%
exactly on time or at the exact time mentioned
On the dot, Wade.
Nonsense. Bang on the dot, as usual.

定義：Oxford Advanced Learner's Dictionary 第 9 版