halcyon \HAL-see-uhn\, noun:
1. A kingfisher.
2. A mythical bird, identified with the kingfisher, that was fabled to nest at sea about the time of the winter solstice and to calm the waves during incubation.

adjective:
1. Calm; quiet; peaceful; undisturbed; happy; as, "deep, halcyon repose."
2. Marked by peace and prosperity; as, "halcyon years."