Other forms: barometers
A barometer is the instrument that measures the pressure of the air, which is how it tells you what the weather is about to do. The brass dial in a hallway with RAIN, CHANGE and FAIR printed round the edge, the one you tap with a fingernail to see which way the needle jumps.
Pressure falling means wind and rain on the way; pressure rising means it is clearing up. The adjective is barometric, as in barometric pressure, which is what a forecast means by a high and a low. Barometer is also used for anything that shows which way a situation is moving: house prices as a barometer of the economy, a by-election as a barometer of the public mood. In that use it takes OF — a barometer of something. The instrument itself is a barometer for weather, never a barometer of it.
1nounbarometerAn instrument that measures air pressure, used to forecast the weather.
“The barometer had been dropping steadily all afternoon.”
2nounanythingAnything taken as a sign of how a situation is changing.
“Ticket sales are a reliable barometer of how the show is doing.”
barometer is an instrument.
Robert Boyle coined the name in 1665, for an instrument Torricelli had already built some twenty years earlier, by putting together baro- and -meter. The name stuck to the object so firmly that other languages then borrowed the word straight back out of English.
Proto-Indo-European
*gʷreh₂-
English, today
barometer
From baro- + -meter. Coined in 1665 by Robert Boyle as a name for the instrument invented by Torricelli some 20 years earlier; soon thereafter borrowed from English into various languages.
Etymology from Wiktionary, CC BY-SA
Practised in Science & Space, Weather & Seasons, Antiques & Collecting