University of Queensland academic Stephen Hughes found that entries for the word 'siphon' incorrectly said atmospheric pressure is the force that allows the device to move liquids from one place to another.
"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," he said.
"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," he added.
Looks like the new version of the dictionary will have the corrected definition. Good for him!
Now let's see if someone else can find other errors. Wikipedia doesn't count, because there's already too many! :)
Edit: more coverage of this at PhysOrg.