Hydrodynamic
/ˌhaɪdroʊdaɪˈnæmɪk/adjective
Relating to the forces exerted by a moving liquid, or shaped to pass through one easily.
The Greek roots
Literally: “of water's force”
The story of the word
Most of the adjective's working life is in engineering rather than physics lectures. A hydrodynamic bearing carries a shaft on a wedge of oil that the shaft's own rotation drags underneath it, so nothing metal ever touches anything metal; that trick keeps ships' propeller shafts and power station turbines alive. Swimmers and hull designers borrowed the word from there, and it behaves as the water twin of aerodynamic because both fluids obey the same equations.
- How it travelled
- Ancient Greek → Modern Latin → English
- First recorded
- 19th century
Same family
In a sentence
The suit is marketed on hydrodynamic drag, which the governing body now limits.
A hydrodynamic bearing needs oil pressure before it needs anything else.