What does Achillēus mean in Latin?

Achillēus, a adjective, means “of or pertaining to Achilles (a Greek epic hero); Achillean”.

How do you pronounce Achillēus?

In classical Latin, [a.kʰɪlˈleː.ʊs]; in ecclesiastical (church) Latin, [a.kilˈlɛː.us].

adjectivefirst/second-declension adjective

Achillēus (feminine Achillēa, neuter Achillēum)

Classical[a.kʰɪlˈleː.ʊs]Ecclesiastical[a.kilˈlɛː.us]

singular
form	masculine	feminine	neuter
nominative	Achillēus	Achillēa	Achillēum
genitive	Achillēī	Achillēae	Achillēī
dative	Achillēō	Achillēae	Achillēō
accusative	Achillēum	Achillēam	Achillēum
ablative	Achillēō	Achillēā	Achillēō
vocative	Achillēe	Achillēa	Achillēum

plural
form	masculine	feminine	neuter
nominative	Achillēī	Achillēae	Achillēa
genitive	Achillēōrum	Achillēārum	Achillēōrum
dative	Achillēīs	Achillēīs	Achillēīs
accusative	Achillēōs	Achillēās	Achillēa
ablative	Achillēīs	Achillēīs	Achillēīs
vocative	Achillēī	Achillēae	Achillēa

Charlton Lewis's shorter dictionary for students: the same scholarship in plain, modern definitions.

Achillēus adj.,

of Achilles, V., O.

Borrowed from Ancient Greek Ᾰ̓χῐ́λλειος (Ăkhĭ́lleios), from Ᾰ̓χῐλλεύς (Ăkhĭlleús) + -ιος (-ios). By surface analysis, Achillēs + -ēus.