This word is acceptable for play in the US & UK dictionaries that are being used in the following games:

• Lexulous
• Wordscraper
• Wordosaur

n. the act or process of starting a process or machine

n. a new organization or business venture

"He left to join what he called a startup, which I later discovered was eight years old."

commencement    beginning    start   

kick-start    hot-wire    restart    crank up    re-start   

upstart   

logon    login    shutdown    standalone    startups