Where does “Suurbritannia” come from?

Suurbritannia (Estonian) comes from Estonian suur, from Proto-Finnic suuri, from Proto-Germanic stūra-.

Ancestry of “Suurbritannia”, step by step

Suurbritannia traces back through two separate lines of ancestry.

via Estonian suur

StepLanguageWordMeaning
1Estoniansuurlarge, big
2Proto-Finnicsuuribig, large
3Proto-Germanicstūra-—

via Estonian Britannia

StepLanguageWordMeaning
1EstonianBritannia—
Every word from Proto-Germanic stūra- →Every word from Proto-Finnic suuri →Every word from Estonian suur →