Questions & Answers about Перед ужином я вымыл руки.
Because перед normally takes the instrumental case.
So:
- ужин = dinner
- перед ужином = before dinner
This is a very common pattern:
- перед работой = before work
- перед сном = before sleep / before going to bed
- перед уроком = before class
So ужином is simply the instrumental singular form of ужин.
Here перед means before in a time sense.
Russian перед can be used in two main ways:
- spatial: in front of
- перед домом = in front of the house
- temporal: before
- перед ужином = before dinner
In this sentence, because ужин is an event/time, the meaning is clearly temporal: before dinner.