What does Esma mean?

At the borrel she ordered an esma instead of a beer for a change.

Dutch student slang. This is a Dutch word. You will hear it a lot at Dutch universities, student associations and in student houses.

The cocktail is vodka, coffee liqueur and a shot of espresso, served in a martini glass with a few coffee beans on top. Party and caffeine in one. Dutch students love shortening drink names, see also baco and cappu. Also read what vino means.