Where does “sky-high” come from?

sky-high (English) comes from English high, from Middle English heigh, from Old English hēah, from Old English hām, from Proto-West Germanic haim, from Proto-Germanic haimaz, from Proto-Indo-European ḱóymos, from Proto-Indo-European ḱey- — to be lying down; to settle.

sky-high (English): extremely tall; excessive, exorbitant

Definitions

  1. extremely tall; excessive, exorbitant

Ancestry of “sky-high”, step by step

sky-high traces back through two separate lines of ancestry.

via English high

StepLanguageWordMeaning
1EnglishhighElevated, extending above a base or average...
2Middle Englishheighhigh; Alternative form of hey; Alternative form...
3Old Englishhēahhigh, tall, lofty, high-class, exalted, sublime,...
4Old Englishhāmhome; village, community; village, hamlet, manor,...
5Proto-West Germanichaimhome
6Proto-Germanichaimazhome; house; village
7Proto-Indo-Europeanḱóymosof the home, belonging to the family; village,...
8Proto-Indo-Europeanḱey-to be lying down; to settle

via English sky

StepLanguageWordMeaning
1EnglishskyThe atmosphere above a given point, especially as...
2Middle EnglishskyThe atmosphere or sky; that which lies above the...
3Old Norseskýcloud
4Proto-Germanicskiwjącloud; sky
5Proto-Indo-European(s)kewH-to cover, bedeck; cover
Every word from Proto-Indo-European ḱey-Every word from Proto-Indo-European ḱóymosEvery word from Proto-Germanic haimaz