The surname Omodei is of anthroponymic origin and derives from the medieval name Omodeo, which continues the Latin form Homodeus, with the meaning "man of God" or "consecrated to God". On this point E. De Felice and E. Rossoni agree, noting that it is a name diffused in the Middle Ages, documented early in different areas of Italy.

Along the same lines, E. Rossoni specifies that this name, also of Franco-medieval tradition, could have been attributed in some cases to foundlings for reasons of a religious or charitable character. Likewise, both authors document its use in various historical contexts, which confirms its consolidation as a personal name and its subsequent transformation into a hereditary surname.