What does octaëdricus mean in Latin?

octaëdricus, a adjective, means “octahedral, of or pertaining to an octahedron”.

How do you pronounce octaëdricus?

In classical Latin, [ɔk.taˈɛ.drɪ.kʊs]; in ecclesiastical (church) Latin, [ok.taˈɛː.dri.kus].

adjectivefirst/second-declension adjective

octaëdricus (feminine octaëdrica, neuter octaëdricum)

Classical[ɔk.taˈɛ.drɪ.kʊs]Ecclesiastical[ok.taˈɛː.dri.kus]

adjectiveoctahedral, of or pertaining to an octahedron
Nihil itague profecimus nisi pateat modus, guo calor internus guttam vapidam in tribus diametris, forma octaedrica vel certe sexangula firmet, ut ad eas fiat materiae per condensationem collectio.And so we have made no progress unless a way is open, in which the internal heat hardens the vaporous drop in three dimensions in an octahedral or certainly a six-angled shape, so that an accumulation of material can be made to them through condensation.1611, Johannes Kepler, Strena seu De Niva Sexangula, page 17:

singular
form	masculine	feminine	neuter
nominative	octaëdricus	octaëdrica	octaëdricum
genitive	octaëdricī	octaëdricae	octaëdricī
dative	octaëdricō	octaëdricae	octaëdricō
accusative	octaëdricum	octaëdricam	octaëdricum
ablative	octaëdricō	octaëdricā	octaëdricō
vocative	octaëdrice	octaëdrica	octaëdricum

plural
form	masculine	feminine	neuter
nominative	octaëdricī	octaëdricae	octaëdrica
genitive	octaëdricōrum	octaëdricārum	octaëdricōrum
dative	octaëdricīs	octaëdricīs	octaëdricīs
accusative	octaëdricōs	octaëdricās	octaëdrica
ablative	octaëdricīs	octaëdricīs	octaëdricīs
vocative	octaëdricī	octaëdricae	octaëdrica

From octaedron (“octahedron”) + -icus (“-al”).