Cowboy Ventures founder and managing partner Aileen Lee describes the circumstances that spurred her to coin the term “unicorn” to refer to billion-dollar startups. As the managing partner of a new $40 million fund, she started investigating the billion-dollar companies that had been born over the previous ten years. She quickly realized that there were many commonalities: founders in their 30s and 40s (not mid-20s dropouts), for example, and founding teams rather than solo founders.