The PIE root refers to the “Proto-Indo-European root,” which is a concept used in historical linguistics. Proto-Indo-European (PIE) is the hypothetical common ancestor of the Indo-European languages, which includes a wide range of languages spoken in Europe and Asia.

A PIE root is a basic morpheme from which various words in different Indo-European languages are derived. These roots are reconstructed by linguists based on comparative studies of descendant languages. For example, the PIE root *bher- means “to carry,” and it has descendants in many languages, such as Latin “fero” (I carry), Greek “pherein” (to carry), and English “bear.”

If you are looking for specific PIE roots or have a particular word or concept in mind, please let me know, and I can provide more detailed information.