By what definition is AirBNB a startup? Edit: downvote me all you want, but a if company with a $1,000,000,000 valuation is a "startup" the word has lost any m

By what definition is AirBNB a startup? Edit: downvote me all you want, but a if company with a $1,000,000,000 valuation is a "startup" the word has lost any meaning.