Reconstruction:Proto-Celtic/dindu

Obvious cognates include Proto-Germanic *tindaz (“peak, pinnacle”) and, as a name borrowed from Phrygian, Ancient Greek Δίνδυμον (Díndumon, name of a mountain).^[1][2]

It is unclear how these cognates are related, however.

• Due to the irregular shape of a hypothetical common inherited root *deyndʰ-, Lucht believes the word must have been a Wanderwort transmitted into Phrygian, Germanic and Celtic from elsewhere.^[2]
• Kroonen instead derives the Celtic and Germanic words as secondary derivatives of *h₃dónts (“tooth”), or more specifically *h₃dént-u- for Celtic.^[3] This etymology poses major phonetic problems in that it is incompatible with Ancient Greek Δίνδυμον (Díndumon), as **Τέντυμον (**Téntumon) would be expected from such a derivation. It also would require a pre-Celtic voicing assimilation of the second dental consonant to *d, because otherwise one would expect **-ddynt to appear in Welsh, not -ddyn.

*dindu n^[1][4]

1. hill
2. citadel, stronghold (stereotypically constructed on hills or comparable high ground)

• Proto-Brythonic: *dɨnn
  • ⇒ Middle Welsh: murddin (“fortification”)
    • Welsh: murddun, murddyn (“ruins”)
  • ⇒ Middle Welsh: trefdyn (“homestead”)
  • ⇒ Middle Welsh: tyddyn, tytyn, tedyn
    • Welsh: tyddyn
  • ⇒ Proto-Brythonic: *gwėlɨɣðɨnn
    • Breton: gouelezenn (“lees, dregs”)
    • Middle Welsh: gwelyddyn (“grave; lees, dregs, sediment”)
• Old Irish: dind
  • Middle Irish: dind, dinn