Definition of eth
- an Old English letter, ð or Ð, representing the dental fricatives /T͟H/ and /TH/. It was superseded by the digraph th, but is now used as a phonetic symbol for the voiced dental fricative /T͟H/ in the International Phonetic Alphabet (IPA) system. Compare with thorn (sense 3).
from Danish edh, perhaps representing the sound of the letter