halcyon
adjective /ˈhælsiən/
/ˈhælsiən/
[usually before noun] (literary)- (of a period of time in the past) peaceful and happy
- the halcyon days of her youth
Word Originlate Middle English (in the mythological sense): via Latin from Greek alkuōn ‘kingfisher’ (also halkuōn, by association with hals ‘sea’ and kuōn ‘conceiving’).