Large crabgrass is a type of weedy grass that can often be found in lawns across the United States. While this pest can be a nuisance for homeowners, there are many different synonyms for the term that may help gardeners and landscapers better understand the plant. Some of the most common synonyms for large crabgrass include digitaria sanguinalis, hairy crabgrass, and hairy finger-grass. Other terms that are used to describe this plant include Indian doab, summergrass, and pigeon grass. No matter what you call it, large crabgrass can quickly take over lawns and gardens if not properly managed.