Proto-Baltic: *ap-iā̃ f., *up-iā̃ f. -ia- c., *ūp-iā̃ f.
Meaning: river
Lithuanian: ùpē, dial. ū̃pē, žem. upì-s, ùpis, gen. -piō `Strom, Fluss'
Lettish: upe `Fluss, Bach'
Old Prussian: ape `Bach, kleiner Fluss' V. 62, { apus 'Quell, Braunen' }; ? wupyan 'Wolke'