The literal word comes from the French, and it means 'hat'.

Aside from meaning 'hat' it is also used when giving someone respect, a short way of saying 'hat off' or 'I'm so impressed, I take my hat off'.

chapeau is a French term that means hat.
but chapeau! "by adding an Exclamation mark" is usually used to express appreciation, admiration, approval or respect
It's like when you say:
Kudos! I take my hat off to you! Well done! Hats off! or My hat's off to you

Hat, Quebec. An isolated island in Quebec little men with hairy bacskides roam the countryside. There are documented cases of Chapeau's citizens moving to the big city, but they have generally failed to urbanize.