δέλτα
From LSJ
English (LSJ)
τό, indecl.,
A the letter δέλτα: gen. δέλτατος Democr.20. (Hebr. dāleth 'door'.) II anything shaped like a Δ, esp. island formed by the mouths of a large river, as the Nile, Hdt.2.13, etc.; of the Indus, Str.15.1.33, Arr.An.5.4.1, etc. 2 adverbially, δ. παρατετιλμέναι Ar.Lys.151. III = δελτωτόν, Ptol.Tetr.27.