The jarring word ‘ajar’
By Anatoly Liberman
All modern dictionaries state that the adverb ajar goes back to the phrase on char, literally “on the turn” (= “in the act of turning”). This is, most probably, a correct derivation. However, such unanimity among even the most authoritative recent sources should be taken with caution because reference books tend to copy from one another. Recycling a plausible opinion again and again produces an illusion of solidity in an area notorious for debatable results. That is why it is so interesting to read books published before Skeat’s dictionary (1882) and the OED came out.