What did the gaelic root of the word for God mean?
The earliest written form of the Germanic word God (always, in this usage, capitalized) comes from the 6th-century Christian Codex Argenteus. The English word itself is derived from the Proto-Germanic * ǥuđan. The reconstructed Proto-Indo-European form * ǵhu-tó-m was likely based on the root * ǵhau(ə)-, which meant either "to call" or "to invoke". The Germanic words for God were originally neuter—applying to both genders—but during the process of the Christianization of the Germanic peoples from their indigenous Germanic paganism, the words became a masculine syntactic form.