That was the most illogical Thanksgiving he could ever remember spending, and his thoughts returned wishfully to his halcyon fourteen-day quarantine in the hospital the year before; but even that idyll had ended on a tragic note; he was still in good health when the quarantine period was over, and they told him again that he had to get out and go to war.
There are no more uses of "halcyon" in the book.
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It was used for more things than family reunions, however: Negroes played basketball there, the Klan met there in its halcyon days, and a great tournament was held in Atticus’s time in which the gentlemen of the county jousted for the honor of carrying their ladies into Maycomb for a great banquet.
Harper Lee -- Go Set a Watchman
This is a little exhibition we used to tour around the Continent back in the halcyon days.
Ransom Riggs -- Miss Peregrine’s Home for Peculiar Children