Other forms: speedometers
A speedometer is the dial showing how fast you are going. Check the speedometer, the speedometer read ninety, a broken speedometer.
It is allowed to read high but never low, which is why yours almost certainly overstates your speed by a few per cent. Satellite navigation measures speed a different way and is usually closer to the truth.
1nounspeedometerThe dial showing how fast you are going.
“He glanced at the speedometer and slowed down when he saw the police car.”
speedometer is an instrument.
Speed plus meter, from Greek metron, a measure, coined in the early days of motoring.
Proto-Indo-European
*speh₁-
Proto-West Germanic
*spōdi — prosperity, success
Old English
spēd — success
Middle English
sped — prosperity, good luck, quickness, success
English
speed
English, today
speedometer
From speed + -o- + -meter; by surface analysis, speed + -ometer. speed comes from Middle English sped (“prosperity, good luck, quickness, success”), from Old English spēd (“success”), from Proto-West Germanic spōdi (“prosperity, success”), from Proto-West Germanic spōan, from Proto-Germanic spōaną (“to prosper, succeed, be happy”), from Proto-Indo-European speh₁- (“to prosper, turn out well”). Cognate with Scots spede, speid (“success, quickness, speed”), Dutch spoed (“haste; speed”), German Low German Spood (“haste; speed; eagerness; success”), German Sput (“progress, acceleration, haste”). Related also to Old English spōwan (“to be successful, succeed”), Albanian shpejt (“to speed, to hurry”) and Russian спеши́ть (“to hurry”), Latin spēs (“hope, expectation”), spērō (“hope”), perhaps also to Ancient Greek σπεύδω (“to urge on, hasten, press on”).
Etymology from Wiktionary, CC BY-SA