What does periodicus mean in Latin?

periodicus, a adjective, means “periodic, periodical (returning regularly)”.

How do you pronounce periodicus?

In classical Latin, [pɛ.riˈɔ.dɪ.kʊs]; in ecclesiastical (church) Latin, [pe.riˈɔː.di.kus].

adjectivefirst/second-declension adjective

periodicus (feminine periodica, neuter periodicum)

Classical[pɛ.riˈɔ.dɪ.kʊs]Ecclesiastical[pe.riˈɔː.di.kus]

singular
form	masculine	feminine	neuter
nominative	periodicus	periodica	periodicum
genitive	periodicī	periodicae	periodicī
dative	periodicō	periodicae	periodicō
accusative	periodicum	periodicam	periodicum
ablative	periodicō	periodicā	periodicō
vocative	periodice	periodica	periodicum

plural
form	masculine	feminine	neuter
nominative	periodicī	periodicae	periodica
genitive	periodicōrum	periodicārum	periodicōrum
dative	periodicīs	periodicīs	periodicīs
accusative	periodicōs	periodicās	periodica
ablative	periodicīs	periodicīs	periodicīs
vocative	periodicī	periodicae	periodica

pĕrĭŏdĭcus, a, um, adj., = περιοδικός,

I. that returns at stated times, periodical (post-Aug.), Plin. 20, 3, 8, § 15: typi, Cael. Aur. Acut. 1, 14, 110.

Borrowed from Ancient Greek περῐοδῐκός (perĭodĭkós).