||The analysis as a loanword is less probable if one considers that the underlying root is well represented in Insular Celtic (PIE *treHgʰ- / *treHg̑ʰ- or *tragʰ- / *trag̑ʰ- 'to drain off, to ebb away', cf. Schumacher 2004, 635-36) and that there are nouns from this root belonging to the same semantic field: Old Breton tre, MW trei m. 'ebbtide', Old Irish tráig 'i, m/f' 'ebbtide, beach' < Proto-Brit. *trăgi̯o-. The word for sand could thus originate from an inherited tu-stem cognate with Latin tractus, i.e. Proto-Celtic *traxtus.