E. Cobham Brewer 18101897. Dictionary of Phrase and Fable. 1898.
A time of happiness and prosperity. Halcyon is the Greek for a kingfisher, compounded of hals (the sea) and kuo (to brood on). The ancient Sicilians believed that the kingfisher laid its eggs and incubated for fourteen days, before the winter solstice, on the surface of the sea, during which time the waves of the sea were always unruffled.