Research on theonyms constitutes the onomastic component within theolinguistics, the universal science dealing with the communication about the divine. It is demonstrated in detail that god (Greek theos, Latin deus, German Gott) is both a nomen appellativum (theolexeme) as well as a nomen proprium (theo-onym). With the help of a checklist it is illustrated in which linguistic fields characteristics of theonyms compared to other types of names can be observed and where further research is needed. For example, etymology can reveal the naming motive of the theonyms Zeus, Iupiter and of the theolexemes theos, deus, Slavonic bog und English god / German Gott.