The word "carbonous" generally refers to something containing or resembling carbon. However, there are several synonyms for this word that can be used depending on the context. Some of these synonyms include carbonaceous, carboniferous, and carby. Carbonaceous refers to matter that contains a high amount of carbon and is often associated with rocks and fossils. Carboniferous, on the other hand, is a geological term used to describe a period in Earth's history characterized by the widespread formation of coal deposits. Carby is a more colloquial term that can be used to describe anything that has a distinct or intense carbon-like smell or taste.