How do u spell jetski

You got the correct letters J-E-T-S-K-I - the word is just generally treated as two-words, as in jet ski.

A jet ski is a small machine like a motorcycle that is powered by a jet engine and can travel on the surface of water.

References in periodicals archive (from Thefreedictionary.com):

Summary: The 2015 Lebanon Water Festival kicked off its activities with an international jet ski race held in Jounieh over the weekend -

June 11, 2015 /PRNewswire/ -- SkiSafe insurance announced the expansion of its leading Jet Ski and Personal Watercraft Insurance program to provide coverage for stand-up jet skis. - <SkiSafe(TM) Expands Jet Ski and Personal Watercraft Program>

Dubai: For jet ski enthusiasts and tourists looking to rev up the speed on the waters of Al Mamzar, this should come as some sort of a warning. - <"Too scarred to come back'>

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