Jet Ski is the brand name of a personal watercraft manufactured by Kawasaki Heavy Industries. The name is sometimes mistakenly used by those unfamiliar with the personal watercraft industry to refer to any type of personal watercraft; however, the name is a valid trademark registered with the United States Patent and Trademark Office, and in many other countries. The term "Jet Ski" (or JetSki, often shortened to "Ski") is often mis-applied to all personal watercraft with pivoting handlepoles manipulated by a standing rider; these are properly known as Stand-up PWCs. The term is often mistakenly used when referring to WaveRunners, but WaveRunner is actually the name of the Yamaha line of sit-down PWCs, whereas "Jet Ski" refers to the Kawasaki line. Recently, a third type has also appeared, where the driver sits in the seiza (i.e. kneeling) position. This type has been pioneered by Silveira Customs with their "Samba".

In 1929 a one-man standing unit called the "Skiboard" was developed, guided by the operator standing and shifting his weight while holding on to a rope on the front, similar to a powered surfboard. While somewhat popular when it was first introduced in the late 1920s, the 1930s sent it into oblivion.^{[citation needed]}

Jet, Jets, or The Jets may refer to:

A ski is narrow strip of wood, plastic, metal or combination thereof worn underfoot to glide over snow. Substantially longer than wide and characteristically employed in pairs, skis are attached to boots with bindings, either with a free, lockable, or permanently secured heel.

Originally intended as an aid to travel over snow they are now mainly used recreationally in the sport of skiing.

Skis are also fitted to vehicles dedidcated to traveling over snow such as snowmobiles and snowcats.

The Nordic ski technology was adapted during the early twentieth century to enable skiers to turn at higher speeds. New ski and binding designs, coupled with the introduction of ski lifts and snowcats to carry skiers up mountains, enabled the development of alpine skis. Meanwhile advances in technology in the Nordic camp allowed for the development of special skis for skating and ski jumping.

Ski nomenclature is relatively simple. Examining the ski from front to back along the direction of travel, the front of the ski (typically pointed or rounded) is the "tip", the middle is the "waist" and the rear (typically flat) is the "tail".