What is the significance of the title, Three-Martini Lunch?

The Three-Martini Lunch refers to a mid-century tradition in which men would go for leisurely work-day lunches that were written off as business expenses. They were long enough to allow time for three martinis, and it became known as the three-martini lunch. Cliff describes his father as the king of the three-martini lunch, and the ritual takes place several times throughout the novel. The three-martini lunch symbolizes the boy’s club-like industry, where business deals are made over drinks, smoke, and steak.