As you can see, it can be used quite literally (#1) or more metaphorically to refer to a "things" or a "situation." (2 & 3)
It is also used in questions (#4). "Che cosa" literally means "what thing" but it is used when English would just say "what."
You can also just say "che" or just say "cosa" and they all mean the same thing:
Che cosa fai?
✓
Che fai? ✓
What are you doing?
Cosa fai? ✓
When "che cosa" or its shortened form "cosa" comes before the verb "è" (is), they get joined together by dropping the -a and adding an apostrophe:
Che cosa è? -> Che cos'è?✓ What is it?
Cosa è? -> Cos'è?✓ What is it?
Note: this only happens when 'cosa' is used as 'what'. In the other contexts, 'cosa' and 'è' remain separate:
La cosa è difficile spiegare.✓
The thing is difficult to explain.
As the most used noun, it isn't hard to find examples in books, film and music. Let's look at different song titles and decide whether it should be translated as: thing/things or what?: (Select the area after each line to reveal my answer) Then, listen to each song and see if you can pick out "cosa" in context… HINT: You might also hear qualcosa which means "something."
As you listen to Italian music and watch Italian shows, be on the look out for cosa once you do, you'll find it everywhere! Also, try writing your own sentence in the comments below!