Dai may refer to:
Names Dai (given name), a Welsh or Japanese masculine given name Dai (surname) (戴), a Chinese surname Bảo Đại (保大), Emperor of Vietnam from 1926 to 1945
Places and regimes Dai Commandery, a commandery of the state of Zhao and in early imperial China Dai County, in Xinzhou, Shanxi, China Dai (Eighteen Kingdoms), a short-lived state during the Eighteen Kingdoms period in Chinese history Dai (Han dynasty), a realm and title during the Han dynasty Dai (Sixteen Kingdoms), a Xianbei-led dynastic state during the Sixteen Kingdoms era of Chinese history Dai (Spring and Autumn period), a state during the Spring and Autumn period in Chinese history Dai (Warring States period), a short-lived state during the Warring States period in Chinese history
People and language Da'i al-Mutlaq, or Da'i, a type of religious leader in Islam Da'i, person engaging in Dawah, the act of inviting people to Islam Dai language (disambiguation) Dai people, an ethnic minority of China Dai (Yindu), or Daai Chin, an ethnic tribe of Chin, Myanmar
Other uses Dai (spider), a genus of Chinese spiders Dai (cryptocurrency), a cryptocurrency-backed stablecoin DAI Personal Computer, an early home computer from Belgium Mercedes-Benz Group's former Frankfurt Stock Exchange stock symbol De Administrando Imperio, work written by the 10th-century Byzantine Emperor Constantine VII Deutsches Archäologisches Institut, or German Archaeological Institute, an archaeological institute operated by the German ministry of foreign affairs DAI Global, an international development firm Diamond Aircraft Industries, an aircraft manufacturer Diffuse axonal injury, a type of traumatic brain injury Digital Author Identifier, a unique number for an author in the Dutch research system Direct audio input, a port used in hearing aids and hearing instruments Distributed artificial intelligence, a subfield of artificial intelligence Do As Infinity, a Japanese band Dragon Age: Inquisition, a video game by BioWare Dynamic ARP Inspection, a security protocol