Where does “rēdi” come from?

rēdi (Proto-Celtic) comes from Proto-Indo-European h₁réh₁-dʰi, from Proto-Indo-European h₁réh₁, from Proto-Indo-European h₁er- — earth.

Ancestry of “rēdi”, step by step

StepLanguageWordMeaning
1Proto-Indo-Europeanh₁réh₁-dʰi—
2Proto-Indo-Europeanh₁réh₁sparsely, rarely, loosely
3Proto-Indo-Europeanh₁er-earth
Every word from Proto-Indo-European h₁er- →Every word from Proto-Indo-European h₁réh₁ →Every word from Proto-Indo-European h₁réh₁-dʰi →