Definition of "palmy"

From Greenland’s icy mountains,From India’s coral strand,Where Afric’s sunny fountainsRoll down their golden sand;From many an ancient river,From many a palmy plain,They call us to deliverTheir land from error’s chain.

1819, Reginald Heber, The Missionary Hymn‎

Elliston was, in his day, the Napoleon of Drury Lane; but, like the conqueror at Austerlitz, he suffered his declensions, and the Surrey became to him a Saint Helena. However, once an eagle always an eagle; and Robert William was no less aquiline in the day of adversity than in his palmy time of patent prosperity.

1832, The London Spy, volume 2, page 292

“It must have been just like the palmy days of the British Drama.”

1891, Oscar Wilde, chapter IV, in The Picture of Dorian Gray, London, New York, N.Y., Melbourne, Vic.: Ward Lock & Co., page 73

So, all things being equal, from the beginning of my stay with Travis, I was in as palmy and benign a state as I could remember in many years.

1967, William Styron, The Confessions of Nat Turner, Vintage, published 2004, page 48

Not many people would argue with his opening insight—that in 1939 people attending the World's Fair gobbled up the optimistic view of the future offered in Flushing Meadows, while people now, in much palmier times than in the late Depression, with World War II looming, are generally pessimistic.

1995 May 21, Steven Levy, “The Unabomber and David Gelernter”, in The New York Times‎