Short this word may be, but its history stretches far back into the mists of time.
It makes its appearance early in English and until around 1200 it was used to mean “cloud”, but the sense quickly evolved to mean more generally “sky” and by extension “heaven” or “the heavens”. Various spellings were employed for the word, such as skeu, skeue and skiwe. Consider this example from the Ancrene Wisse, from around 1230:
Wið uten us al þe world leitinde o swart lei up in to þe skiwes.
(Outside us, all the world lighting the darkness up into the skies)
You might expect the trail to be an easy one from there further back into the past, and indeed the problem is not finding the trail, but working out which one is the right trail to follow!
Let’s look first at what the Oxford English Dictionary tells us, which is that “sky” comes from the Old Norse word ský. Here is an example of Old Norse, from Grímnismál of the Poetic Edda:
En ór hans brám
gerðo blið regin
miðgarð manna sonom;
en ór hans heila
vóro þau in harðmóðgo
ský öll um sköpuð.
(And of his brows
did the gentle powers
Midgard for the sons of men;
but from his brain
was the mind-wondering
cloud all created.)
The date of Grímnismál is uncertain, but a number of scholars believe that the type of language used shows that it was written in the 12th or 13th century. You might think that it is clear cut: the Old Norse word is so tantalisingly similar to the Modern English one. But it is not as simple as that, and forms in Middle English such as skeu or skewe persisted for several centuries, such as seen here, in the Middle English romance Gest Historiale of the Destruction of Troy from about 1540:
A laite..skirmyt in the skewes with a skyre low, Thurgh the clater and clowdes clos to the heuyn
(A light … darts in the skies with a low mist, Through the bustle and clouds, close to the heavens’.)
This brings me onto the next point. It is generally thought that the Old English word for “cloud”, sceó, is a cognate of the Old Norse ský, but ultimately not the predecessor of the Modern English sky. Here is an example of the Old English, from the Codex Exoniensis (or Exeter Book) from 960:
Scearp cymeþ sceó wið óðrum, ecg wið ecge
(of the coming together of clouds charged with energy)
I see no difference between the way sceó is used to mean “cloud” here and the way ský is used to mean cloud, and the words are in any case very similar. Although spellings can sometimes be a good indicator of a word’s provenance, this is by no means always the case. We must also consider the continuing usage of forms such as skewes (seen above), skeu, scue, and so on, all after the supposed adoption of the Old Norse word, and all somewhere between the Old Norse and the Old English form. They can be seen alongside such examples as scki, sci, skei, skige, all generally agreed to have derived from the Old Norse form. Not only this, but there does not seem to be a clear regional distinction in forms used in areas under the Danelaw (northern and eastern England on today’s map), and therefore considered more heavily influenced by Old Norse, and forms in other areas. I also feel that vowel evolution from sceó to sky is neither impossible nor improbable – one need only look at the accepted source for both words from Proto-Germanic (see below) to ascertain that. Given these points, I would like to propose a different theory: that the modern English word sky came from a merging of Old Norse and Old English forms.
Now let’s take one step further back into the past. Not surprisingly, both sceó and ský can be traced back to the same source: Proto-Germanic *skeujam, meaning “cloud” or “cloud cover”. The trail doesn’t end there, of course. Take note of the second meaning given for *skeujam, and consider that words meaning “shadow”, such as Old Norse skuggi, are also thought to originate from there.
The next step is to go to Proto-Indo-European root *skeu, meaning “cover, conceal”. There could be a distant link with Greek verb σκεπάζω (skepazo), meaning “cover”, but this is a point that requires further investigation.
Interestingly, *skeu is also thought to ultimately be the source of the English word “hide”, which I intend to write about more fully in a separate article.