Generally, "realia" means "real things".

In the library world, realia are objects such as puppets, rocks, globes, sculptures, and other items that cannot be classified as a book, recording, or any other kind of thing.

The term "realia" is also used in language education to mean genuine objects and materials from the culture associated with the language being learned. For example, students would use train timetables, boxes from a grocery store, common paperwork forms, and other objects that native speakers would ordinarily encounter in daily life.