Cognomen コイ (Khoi 
, Coy 
, Koy ) , throughout the world, is a common surname. The surname コイ is characteristic of Latin America and the Caribbean, particularly British Virgin Islands, where it is quite a common surname, Guatemala, and Belize (explore the name in all countries). Not in comparison with a country's population, it is the most numerous in Indonesia, the United States, and Guatemala. Much less frequently, コイ is the forename as well as the last name.