What is the name for the study of the origin and history of words?

The study of the origin and history of words is called etymology.

Etymology examines how words began, changed form, shifted meaning, and moved between languages. Researchers compare older documents, regional dialects, pronunciation patterns, and related languages. When direct records are missing, they may use the comparative method to reconstruct an earlier ancestral form, such as a word from Proto-Indo-European.

The term comes from Ancient Greek étymos, meaning “true” or “real,” combined with -logia, meaning the study or account of something. Etymology is closely connected with historical linguistics and philology, but it is not the same as phonology, which studies a language’s sound system. It is also unrelated to entomology, the study of insects, despite the similar spelling.

Modern etymology became more systematic in the 18th century, as scholars began identifying regular relationships among languages. In 1786, William Jones argued that Sanskrit, Greek, and Latin shared a common ancestry, helping lay the foundation for Indo-European studies. An individual word’s history can also be called its etymology.