halcyon
Pronunciation: /ˈhalsɪən, -ʃ(ə)n/
adjective
noun

Origin:
late Middle English (in the mythological sense): via Latin from Greek alkuōn 'kingfisher' (also halkuōn, by association with hals 'sea' and kuōn 'conceiving')

Spelling help
Remember that halcyon ends with -cyon.