What is "three card brag"

n. (context chiefly British English) A card game somewhat like a simplified form of poker, and one of poker's several ancestors.

Three-card brag is a 16th-century British card game, and the British national representative of the vying or "bluffing" family of gambling games. Brag is a direct descendant of the Elizabethan game of Primero and one of the several ancestors to poker, just varying in betting style and hand rankings.

A variant of the game is very popular in Trinidad, India, Bangladesh and Nepal, where it is known both as "flush" and (literally 'three cards' in Hindi), played with numerous local variations. At large gatherings and especially during festival times, it is the game of choice since many people of different skills can play together and have fun. It is also a very popular game among British fairground showmen, who usually get together at the bigger fairs and play for quite high stakes.