English from Greek "pure".
Introduced into Scotland in the 13th century by returning Crusaders. The English and German spelling variant Katharine [q.v.] is preferred in US.
The main spellings in the 1841 Census of Aberdeenshire are Catharine [25%], Catherine [60%], Katharine [4%], Katherine [4%]. There are many other, less frequent variations in spelling, some of which are shown under Catherine [q.v.].
TThe FreeREG list of Latin names used in old documents shows Catalina as being the equivalent of Catherine and Catherina/Katherina/Katalina being the equivalent of Katherine. We are not convinced that such subtle differentiation is entirely consistent. Whatever the truth of it, care is needed when searching old documents as clearly there will be some variation in the names, even as there is today. Use truncated names [e.g. Catherin*] to avoid difficulties with Latin case endings.
Note Some details, where specific, are included under Katharine, Catherine and Catharine but, as in the Oxford Names Companion, we have given the most complete set of relationships here, under Katherine.