Genus Hirundo refers to a group of birds commonly known as swallows. Synonyms for this term could include genus Delichon, which specifically refers to the species of swallows found in Europe and Asia. Another synonym could be the family Hirundinidae, which encompasses all species of swallows worldwide. Additionally, the term "martin" is often used to refer to certain species within the genus Hirundo, such as the American cliff swallow (Hirundo pyrrhonota) or the purple martin (Progne subis). Overall, there are many different terms and synonyms that can be used to refer to this fascinating group of birds known for their long, graceful wings and impressive aerial acrobatics.