The lowercase version has been adopted to represent a voiced dental fricative (IPA: [ð]) in the International Phonetic Alphabet.

In Icelandic, ⟨ð⟩, called "eð", represents an alveolar non-sibilant fricative, voiced [ð̠] intervocalically and word-finally, and voiceless [θ̠] otherwise, which form one phoneme, /θ/.

In Olav Jakobsen Høyem's version of Nynorsk based on Trøndersk, ⟨ð⟩ was always silent, and was introduced for etymological reasons.

A study of Mercian royal diplomas found that ⟨ð⟩ began to emerge in the early 8th century, with ⟨ð⟩ becoming strongly preferred by the 780s.

⟨þ⟩ in turn went obsolete by the Early Modern English period, mostly due to the rise of the printing press,[4] and was replaced by the digraph ⟨th⟩.