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TERM
DESCRIPTION
HYGROMETER
An instrument that measure relative
humidity of the air. This is expressed as a
percentage between 0% and 100%.
INCHES OF MERCURY
(inHg)
This is the common unit of measurement
for air pressure in the United States. It
refers to the length of a standard column
of mercury (a liquid metal) that can be
pushed up by the ambient air pressure.
Standard pressure is approximately 29.92
inHg
KNOTS (kn)
One knot is equivalent to one nautical
mile and is sometimes used to indicate
wind speed.
LCD
An acronym for “Liquid Crystal
Display.” This is a common type of
display screen used in televisions,
computers, watches, and digital clocks.
LUX (lx)
The unit of illuminance (
a measure of the
intensity of illumination on a surface
) as
used in the SI system.
MILLIBAR (mb)
See HECTOPASCALS.
MM OF MERCURY (mmHg)
This is similar to inches of mercury,
except expressed in millimeters. Standard
pressure is approximately 760 mmHg.
NIST
National Institute of Standards and
Technology. A United States institute
that keeps very accurate time using
atomic clocks and provides and
internet-based service to accurately set
device clocks.
RELATIVE AIR PRESSURE
RELATIVE BAROMETRIC
PRESSURE
Relative air pressure is the absolute air
pressure compensated for the altitude of
the barometer. The result is what the air
pressure would be at sea level.
