the.com/propeller
a screw that lies to water, twisting backward to drag the whole ship forward.
means A rotating shaft fitted with angled blades that pushes against water or air to drive a vessel or aircraft forward.
from From Latin 'propellere,' to drive forward — 'pro-' (forward) plus 'pellere' (to push or strike), the same root that gives us 'expel' and 'compel.' English added the agent suffix '-er' to name the thing that does the pushing. The word arrived in the 18th and 19th centuries alongside the spread of steam power, when inventors were racing to replace paddle-wheels with screw-shaped blades that bit into the water and shoved the ship ahead.
theft originBorrowed straight from Archimedes' ancient water-lifting screw.
cavitationSpin too fast and water boils cold, eating the blades.
tip speedAircraft blade tips can nearly hit the sound barrier.
counter-rotationSome use twin props spinning opposite ways for stability.