What does ōcimum mean in Latin?

ōcimum, a noun, means “basil (Ocimum basilicum)”.

What is the genitive of ōcimum?

The genitive singular is ōcimī. ōcimum is neuter, second declension.

In classical Latin, [ˈoː.kɪ.mũː]; in ecclesiastical (church) Latin, [ˈɔː.t͡ʃi.mum].

noun · neutersecond declension

ōcimum n (genitive ōcimī)

Classical[ˈoː.kɪ.mũː]Ecclesiastical[ˈɔː.t͡ʃi.mum]

basil (Ocimum basilicum)
[…]Ī nunc, 'Dīnomachēs ego sum' sufflā, 'sum candidus.' Estō, dum nē dēterius sapiat pannūcia Baucis,Go now, puff yourself up, 'I am the son of Dinomache, I am shining.' Be then, while only wizened Baucis has worse sense than you, when she nicely sings her basils to some ragged slave.c. 62 CE, Persius, Saturae 4.19–22

ōcĭmum, i, n., = ὤκιμον,

I. basil, Plin. 19, 7, 36, § 119; 20, 12, 48, § 119; Cels. 2, 20; Col. 10, 319; Pers. 4, 21.

Borrowed from Ancient Greek ὤκιμον (ṓkimon).