Cognomen เทียนใจ (เทียนใจ 
, Tienjai 
, Tianjai ) , throughout the world, is a very rare family name. The last name เทียนใจ is characteristic of Thailand, where it is a very rare surname, and the United States, where it is an extremely rare surname. Also, เทียนใจ is the forename as well as the last name.