Borrowed from Anglo-Norman cofre, from Latin cophinus (“basket”), from Ancient Greek κόφινος (kóphinos, “basket”). Dinneen lists this word as a doublet of cómhra. Whether or not they actually were doublets, these forms were used interchangeably, and older written materials (Linguaphone 1929 https://www.xn--mirenghuairim-3db8p.ie/linguaphone-conversational-course-irish/an-taonu-ceacht-ar-fhichid/) and dialectal pronunciations are frequently based on that form.