See also: celticum Latin Etymology Elliptic form of imperium Celticum (“Celtic empire”). Pronunciation (Classical Latin) IPA(key): /ˈkel.ti.kum/, [ˈkɛɫ̪t̪ɪkʊ̃ˑ] (modern Italianate Ecclesiastical) IPA(key): /ˈt͡ʃel.ti.kum/, [ˈt͡ʃɛl̪t̪ikum] Proper noun Celticum n (genitive Celticī); second declension the Celtic nation, the Celts Declension Second-declension noun (neuter).More information singular, plural ... singular plural nominative Celticum Celtica genitive Celticī Celticōrum dative Celticō Celticīs accusative Celticum Celtica ablative Celticō Celticīs vocative Celticum Celtica Close References “Celtae”, in Charlton T. Lewis and Charles Short (1879) A Latin Dictionary, Oxford: Clarendon Press Celticum in Gaffiot, Félix (1934) Dictionnaire illustré latin-français, Hachette.Wikiwand - on Seamless Wikipedia browsing. On steroids.