What does milliō mean in Latin?

milliō, a numeral, means “million”.

How do you pronounce milliō?

In classical Latin, [ˈmɪl.li.oː]; in ecclesiastical (church) Latin, [ˈmil.li.o].

numeralthird-declension one-termination numeral

milliō (genitive milliōnis)

Classical[ˈmɪl.li.oː]Ecclesiastical[ˈmil.li.o]

singular
form	masculine	feminine	neuter
nominative	milliō	milliō	milliō
genitive	milliōnis	milliōnis	milliōnis
dative	milliōnī	milliōnī	milliōnī
accusative	milliōnem	milliōnem	milliō
ablative	milliōnī milliōne	milliōnī milliōne	milliōnī milliōne
vocative	milliō	milliō	milliō

plural
form	masculine	feminine	neuter
nominative	milliōnēs	milliōnēs	milliōnia
genitive	milliōnium	milliōnium	milliōnium
dative	milliōnibus	milliōnibus	milliōnibus
accusative	milliōnīs milliōnēs	milliōnīs milliōnēs	milliōnia
ablative	milliōnibus	milliōnibus	milliōnibus
vocative	milliōnēs	milliōnēs	milliōnia

millĭo, ōnis, m.,

I. a kind of hawk, Macr. Emp. 33.

Calque of Old Italian milione (“million”), from mille (“thousand”) (from Latin mīlle) + the augmentative suffix -one (from Latin -ōnem).