How it’s served
Straight up
Straight up usually means the same as "up": chilled with ice, then strained into a glass without ice. Some people use it to mean neat, so it's worth checking.
In practice
If you order a whiskey straight up, ask whether the bartender takes it to mean chilled and strained or poured neat. For cocktails it almost always means served up, like a Martini in a cocktail glass.
Drinks to try it with
Straight up, in short
What does straight up mean?
Straight up usually means the same as "up": chilled with ice, then strained into a glass without ice. Some people use it to mean neat, so it's worth checking.