Variant of Katherine, from Greek 'katharos' meaning pure or clear.
Kathrine is one of the cleaner alternate spellings of Katherine, a name whose history is among the longest and most illustrious in the Western naming tradition. The name traces ultimately to the Greek *Aikaterine*, whose etymology has been debated for centuries: some scholars connect it to the Greek *katharos* (pure, unsullied), a derivation that became so accepted that the medieval Latin form *Catharina* was often glossed as meaning "pure"; others propose a pre-Greek origin, possibly Coptic or related to the goddess Hecate. The early Christian martyr Katherine of Alexandria — who according to tradition confounded fifty pagan philosophers in theological debate before her execution on a spiked wheel — made the name enormously popular across medieval Europe, and the Catherine wheel she was martyred on became both an instrument of torture and a firework design.
From that singular, stormy origin the name spread into virtually every European language: Caterina, Catalina, Katarzyna, Ekaterina, Karen, Kay — an extraordinary proliferation that produced queens, saints, writers, and scientists across a thousand years. Catherine of Aragon and Catherine the Great represent opposite poles of the name's historical range, from patient suffering to audacious power. The literary Catherines — Brontë's wild Catherine Earnshaw, Austen's sensible Catherine Morland — add further dimension.
The Kathrine spelling, dropping the middle vowel of "Katherine" and the *C* of "Catherine," creates a name that is immediately recognizable yet distinctly individual. It was notably borne by Kathrine Switzer, who in 1967 became the first woman to officially run the Boston Marathon under her own name, making the spelling associated with a particular kind of quiet determination and barrier-breaking courage.