The term start-up refers to a company in the first stages of operations. Start-ups are founded by one or more entrepreneurs who want to develop a product or service for which they believe there is demand. These companies generally start with high costs and limited revenue, which is why they look for capital from a variety of sources such as venture capitalists.
A unicorn is any privately owned firm with a market capitalization of more than $1 billion. It denotes new entities dedicated to offering creative solutions and new business models, among other things.