What does cīnēmatēum mean in Latin?

cīnēmatēum, a noun, means “cinema, movie theater”.

What is the genitive of cīnēmatēum?

The genitive singular is cīnēmatēī. cīnēmatēum is neuter, second declension.

In classical Latin, [kiː.neː.maˈteː.ũː]; in ecclesiastical (church) Latin, [t͡ʃi.ne.maˈtɛː.um].

noun · neutersecond declension

cīnēmatēum n (genitive cīnēmatēī)

Classical[kiː.neː.maˈteː.ũː]Ecclesiastical[t͡ʃi.ne.maˈtɛː.um]

cinema, movie theater
[…]diebus Lunae, Martis (fortasse etiam Mercurii) monstrabuntur in cinemateo[…][…] on Mondays, Tuesdays (maybe even Wednesdays) they will be shown in the cinema […]1987, Hermes Americanus, Academia Latina Danburiensis, page 314:
Magístra Quid facis diē Sātúrnī vésperī? Dorothḗa Intérdum eō in cīnēmatḗum.Teacher What do you do on Saturday evening? Dorothy Sometimes I go to the movie theater.2007, John C. Traupman, Conversational Latin for Oral Proficiency: Phrase Book and Dictionary, Classical and Neo-Latin, 4th edition, Wauconda, Ill.: Bolchazy-Carducci Publishers, Inc., →ISBN, page 40:

Blend of Ancient Greek κίνημα (kínēma, “movement”) (in the modern sense of English cinema) and Ancient Greek ᾠδεῖον (ōideîon, “music hall”).