I know what it means, how to use it in a sentence, but where does it come from? Was there ever such a thing as a kilter? I often say I am off-kilter. Can I ever say I am back on kilter? Thank you!
The earliest-recorded use of the word in print - when it was spelt 'kelter' - was in the 1640s. At that time, it was used in dialects throughout England to mean "good condition". Hence, 'out of kelter/kilter' meant not quite right. The etymology is unknown.