What does bibliopōlīum mean in Latin?

bibliopōlīum, a noun, means “bookshop, bookstore”.

What is the genitive of bibliopōlīum?

The genitive singular is bibliopōlīī. bibliopōlīum is neuter, second declension.

noun · neutersecond declension

bibliopōlīum n (genitive bibliopōlīī)

Borrowed from Ancient Greek βῐβλῐοπωλεῖον (bĭblĭopōleîon, “a bookseller’s shop, a bookstore”).