An Australian physicist has found a basic error in the definition of the word 'siphon', which may have existed in dictionaries and text books around the world for almost a century.
The error, first found in the Oxford English Dictionary, has existed since 1911 according to Queensland University of Technology lecturer Dr Stephen Hughes.
He says, the dictionary incorrectly states that atmospheric pressure is what causes a siphon to move water.
"It is gravity that moves the fluid in a siphon, with the water in the longer downward arm pulling the water up the shorter arm."
According to Hughes, water flowing through a siphon acts as a chain, with the lower end pulling down the water above.
Hughes first detected the error while writing an article for the journal Physics Education, about a siphon he observed transferring water from the River Murray into Lake Bonney in South Australia.
He was surprised to find most dictionaries had the wrong definition.
"An extensive check of online and offline dictionaries did not reveal a single dictionary that correctly referred to gravity being the operative force in a siphon."
Oxford English Dictionary spokesperson Margot Charlton says this the first time someone has queried the definition.
"The OED entry for siphon dates from 1911 and was written by editors who were not scientists," she wrote in a reply to Hughes.
"Our files suggest that no-one has queried the definition before. We are revising that entire dictionary text now, and I have copied your helpful comments to the revision file, to ensure they are taken into account when the entry is rewritten."
Hughes is concerned that this may not be the only instance of the incorrect definition.
"I would be very grateful if readers could let me know if the siphon misconception exists in dictionaries of other languages, and also if school teachers could let me know of either correct or incorrect definitions of the siphon in school text books," he says.
Sue Butler, editor of the Australian Macquarie Dictionary, says while their definition of siphon isn't technically wrong, a new updated version is being written.
"I think it was not enough for the dictionary to avoid explaining what happens, so we rewrote our definition and I ran it past him [Hughes] and he had some input into how it was framed," she says.
Butler says the new definition will appear in the online edition towards the end of May, but it will not appear in print for a few years.
She says creating definitions for scientific terms in a general dictionary can be a difficult process.
"You have to understand the science and translate it for the general reader," says Butler. "That presents a real difficulty because quite often you're not going to end up with something scientists are going to be completely happy with."
"If you go too far towards removing technical jargon and simplifying the basic concept, you go can so far that you actually get it wrong."