"Root repetition" typically refers to the recurrence or repetition of the root word in a linguistic context. In morphology, the root is the primary lexical unit of a word, to which affixes or suffixes can be added to form various inflected or derived forms. "Root repetition" then refers to instances where the root of a word is repeated within the word itself or within a related set of words.
For example, in English, "react" is a verb formed from the root "act," and the repetition of the root occurs in the derived word. In linguistics, this repetition can reveal insights into the structure and meaning of words, as well as the historical development of languages.