Q From Paul Nix, UK: Any idea of the origin of the word kilter, as used in out of kilter, to mean not aligned?
A To be truthful, not really. What we do know, though, is that it started out as kelter rather than kilter. In that form it was once widely known in various English and Scots dialects from at least the sixteenth century onwards. It means a state of good health or spirits, or good order. Unfortunately, we’ve no idea where it comes from.
(In the interests of accuracy and completeness, there were several other dialect senses of kelter, including that of money or property, rubbish or litter, silly talk or nonsense, or — as a verb — to move in an undulating manner. The English Dialect Dictionary has a wonderful quote from a Scottish source about this last one: “Eels are said to kelter in the water when they wamble.” To wamble is to turn and twist the body about, roll or wriggle about, or roll over and over.)
Sometime in the seventeenth century, the word started to be spelled kilter, for a reason as much lost in time as the origin of the word itself. For a while, both spellings co-existed — the older one appears in the 1811 edition of Captain Francis Grose’s Dictionary of the Vulgar Tongue: “KELTER. Condition, order. Out of kelter; out of order”, which also gives the money sense. Eventually, the kilter spelling mostly prevailed, though the older version still turns up occasionally.