What does whiskey down mean in a diner?

"Whiskey down" is not a standard phrase used in diners or any other restaurant. It's not a menu item, an order, or a way to describe a drink.

It's likely a mishearing or misunderstanding of something else. Here are some possibilities:

* "Whiskey, down" - This could be someone ordering a whiskey "neat" (straight), or possibly a whiskey "down the hatch" - meaning to drink it quickly.

* "Whiskey, down" - Could be a way of saying they are having a whiskey and then going to sleep/leave.

* "Whiskey, down!" - Could be a cheer, possibly celebrating something.

* "Whisky, dawn" - Possibly a confused order for "whisky, Dawn," meaning a whisky with a mixer called Dawn.

If you heard this phrase in a diner, it's best to ask for clarification.