Poetry

Turning and turning in the widening gyre
The falcon cannot hear the falconer;
Things fall apart; the centre cannot hold;
Mere anarchy is loosed upon the world,
The blood-dimmed tide is loosed, and everywhere
The ceremony of innocence is drowned;
The best lack all conviction, while the worst
Are full of passionate intensity.
Surely some revelation is at hand;
Surely the Second Coming is at hand.
The Second Coming! Hardly are those words out
When a vast image out of "Spiritus Mundi"
Troubles my sight: somewhere in sands of the desert
A shape with lion body and the head of a man,
A gaze blank and pitiless as the sun,
Is moving its slow thighs, while all about it
Reel shadows of the indignant desert birds.
The darkness drops again; but now I know
That twenty centuries of stony sleep
Were vexed to nightmare by a rocking cradle,
And what rough beast, its hour come round at last,
Slouches towards Bethlehem to be born?

-- William Butler Yeats, "The Second Coming"

Word origins

(Cross-posted to gmworkshop.)

I'm looking for the origins of two terms used specifically in the superhero genre (and the second to the large extent elsewhere): "white event", referring to the Big Event when superpowers started appearing in the world, and "psi", referring to psychic powers. I don't have any dictionaries handy other than dictionary.com, which tells me that "psi" is probably short for "parapsychological", but doesn't tell me where or when it originated.

Any help would be appreciated! :)

(EDIT: Looks like I've got 'em. Thanks, mgrasso and cobaltnine!)