We found cupboards that were extra wide dresser originally built into the wall, sometimes made in the deep walls of the country houses and where they kept different things but, essentially, household and food. The typical furniture, already known in the middle Ages (the word comes from Arabic) was made of wood and its place was the kitchen. They used to have open shelves and, in the lower part, drawers or blind doors. Some were closed with lattice doors.
As they were more worked and sophisticated, they also went to the classroom. Surely, when you hear about cupboards you will relate them to country houses and rustic styles. Over time, the differences between cabinets and showcases have been diluted, not even among the uses that you can give to one another.
It is more a question of design (if they have doors or not) and where they are located, whether in the living room or the kitchen. In fact, there are areas where they refer to them without distinction. On the other hand, and in another environment, like the living room they are very useful as bookstores and to exhibit collections or works of art. There are fully glazed cabinets or with a closed low module that can be of doors or drawers.