þriðiu

þriðiu is an Old Norse word. It is the genitive singular form of the word þriðr, which means "third." In Old Norse grammar, the genitive case often indicates possession, origin, or a part of something. Therefore, þriðiu would typically be used in constructions that express "of the third" or "belonging to the third."

For instance, one might encounter þriðiu in phrases like "þriðiu hlutar," meaning "of the third part." The word's usage is tied to the grammatical structure of Old Norse, a North Germanic language spoken in Scandinavia and its colonies from the 7th to the 14th centuries. Understanding the genitive case is crucial for interpreting Old Norse texts accurately.

The root of þriðiu can be traced back to Proto-Germanic *þridjō. The "-u" ending signifies the genitive singular in the masculine and neuter declensions of adjectives and certain nouns in Old Norse. While the word itself is not commonly used in modern Scandinavian languages, its linguistic descendants exist, such as the Swedish "tredje" or the Norwegian "tredje," both meaning "third." The study of such forms provides insight into the evolution of Germanic languages.