Growth hacking, a term coined by Sean Ellis in 2010, refers to strategies aimed at achieving rapid growth for startups through innovative marketing techniques. It encompasses a funnel process that includes user acquisition, activation, retention, revenue, and referral, with an emphasis on testing and optimizing user experiences. Notable examples, such as Airbnb's integration with Craigslist, illustrate the practical application of growth hacking tactics that encourage user engagement and referrals.