Definition

1. Noun:
   • An instrument that indicates the speed of an aircraft relative to the speed of sound: A machmeter is a flight instrument that displays the aircraft's Mach number, which is the ratio of the aircraft's true airspeed to the local speed of sound.

Usage Examples

• Noun:
  • The pilot checked the machmeter to ensure the jet was not exceeding its maximum operating speed.
  • A reliable machmeter is essential for high-speed flight in the transonic and supersonic regimes.

Advanced Usage

• Technical Context: In aviation, the term is used specifically for the cockpit instrument. The reading is crucial for aircraft performance and safety at high speeds.
  • Engineers calibrated the machmeter to provide accurate readings at various altitudes.

Variants and Related Words

• Mach number (n): The dimensionless quantity representing the ratio of speed to the speed of sound, which the machmeter displays.
  • A Mach number of 1.0 indicates the aircraft is traveling at the speed of sound.

Synonyms

• Airspeed indicator (contextual): While a standard airspeed indicator shows indicated airspeed, a machmeter is a specialized type for showing Mach number. They are related but not perfect synonyms.

Notes

• The word is a compound noun formed from "Mach" (named after physicist Ernst Mach) and "meter" (a measuring instrument). It refers specifically to the measuring device itself.

Noun

1. speedometer for measuring the speed of an aircraft relative to the speed of sound