Compound nouns in Bulgarian grammar are formed by combining two or more words to create a single noun with a specific meaning. These compound nouns often highlight a unique characteristic or describe a particular relationship between the components. In Bulgarian, compound nouns can be formed from various combinations, such as noun + noun, adjective + noun, verb + noun, or noun + verb. It’s important to learn and understand compound nouns as they can significantly enrich one’s vocabulary and understanding of the Bulgarian language.