Definition

1. Noun:
   • A unit of pressure: "mm hg" is a unit of pressure equal to 0.001316 atmosphere. It is named after the Italian physicist Evangelista Torricelli, who invented the barometer. This unit represents the pressure exerted by a one-millimeter column of mercury (Hg) at 0°C under standard gravity.

Usage

• "mm hg" is used as a standard unit for measuring pressure, particularly in fields like medicine (for blood pressure), meteorology, and engineering.
• It is often written in lowercase as "mm Hg" or "mmHg".
• It is a non-SI unit but is widely accepted and used.

Examples

• Noun:
  • Normal blood pressure is around 120 over 80 mm hg.
  • The atmospheric pressure dropped to 760 mm hg.
  • The pressure in the tire was measured as 2.1 bar, which is approximately 1575 mm hg.

Advanced Usage

• "mm hg" in scientific contexts: Commonly used in scientific papers and medical reports to express pressure values precisely.
  • The patient's diastolic pressure was recorded at 90 mm hg.

Variants and Related Words

• Torr (n): A unit of pressure approximately equal to 1 mm hg. It is named in honor of Torricelli and is often used interchangeably in vacuum measurements.
  • The vacuum chamber reached a pressure of 0.5 Torr.
• Millimeter of mercury (n): The full name for the unit "mm hg".
  • The pressure was given in millimeters of mercury.

Synonyms

• Torr: A nearly equivalent unit of pressure (1 Torr ≈ 1.000000142 mm hg).
• Millimeter of mercury: The descriptive term for the same unit.

Related Phrases

• "expressed in mm hg": Indicates that a pressure measurement is given using this unit.
  • All blood pressure readings were expressed in mm hg.

Noun

1. a unit of pressure equal to 0.001316 atmosphere; named after Torricelli