In English, this type of construction is called a compound noun: it is used to describe a specific type of something. The final noun is the general thing, and any nouns in front of it (yes, there can be more than one) specify exactly what kind of thing it is.
As an example, a can is a noun, an opener is a noun, and we can put these two nouns together to form a compound noun- a can opener. Opener is the general noun, and can specifies exactly which kind of opener we are talking about.
We can take this one step further: if we have a special kind of can opener that is used to open paint cans, it would be a paint can opener.
In Portuguese, you describe the opener as a possession of the can... "abridor de lata". Clearly, abridor is not a possession of lata, but in the grammar of Portuguese, that is how you use a noun to specify the exact type of another noun.
It is possible to use the same construction in English, however it is uncommon and perhaps has literary overtones- for example, you could say "a user of drugs" rather than "a drug user".
In some situations, the meaning or emphasis of the of-form is different: a water bottle (compound noun) is a bottle whose specific purpose is to contain water. A bottle of water is some water that is contained in a bottle.