They started as same word, but their meanings have drifted apart over time.
Some practical guidance, and interesting history, about a common mistake.
We'll tell you all the perpendiculars
A simple way to keep them apart. (Most of the time.)
Comedian ISMO tries to figure out 'one' and 'two'
The landmark edition that transformed the way dictionaries are made.
Soop, wimmen, and headake did not make the cut