Family name Gagn (Gain 
, Gayn 
, Gagn 
) , around the globe, is a widespread surname. The cognomen Gagn is characteristic of India, where it is quite a common surname, Bangladesh, where it is quite a rare surname, and Qatar. In absolute terms, it is the most numerous in India, Bangladesh, and France. Much less frequently, Gagn is the forename as well as the last name.