There is no one definitive answer to this question, as the meaning of "unicorn status" can vary depending on who you ask. Generally speaking, a unicorn is a startup company that has achieved a valuation of $1 billion or more. This can be through a number of different methods, such as initial public offerings (IPOs) or private equity funding. Because these companies are so valuable, they are often referred to as "unicorns."
There are a limited number of unicorns in the world, which is why they are considered so special. As of March 2018, there were just over 200 unicorns globally, with the majority headquartered in the United States. Some of the most well-known unicorns include companies like Airbnb, Uber, and Pinterest.