Growth hacking is an umbrella term for strategies focused solely on growth. It is usually used in relation to early stage startups who need growth in a short time on a small budget. The goals of growth hacking strategies are usually to acquire as many users or customers as possible while spending as little money as possible.
Growth hacking is accomplished by taking your product and testing it to make sure people want it (and are willing to pay for it). This will help you gather data so you understand your key buyer personas and can target growth marketing tactics accordingly. Simply put, growth hacking is a process of rapid experimentation across marketing funnels, product development, sales segments, and other areas of the business to identify the most efficient ways to grow a business.