means A young company, usually in tech, built to grow fast and find a scalable business model — often burning investor money while racing to become self-sustaining.

from A plain compound of "start" + "up," both old Germanic-rooted English words. "Startup" first meant the act of starting something up — a machine, an engine — before it settled, in mid-20th-century American business slang, onto a newly launched company. The venture-capital sense we use today bloomed alongside Silicon Valley in the late 20th century, when "a startup" came to mean not just any new firm but specifically the lean, fast-growing, high-risk kind.