"Shank of the evening" can mean the latter part of the evening, or it can mean "the best time of the evening," as when the mood and the colors are especially heightened. Whatever it's used to mean, it's not a very common phrase. I used it Wednesday night in a story I was working on, and I don't think I've ever used it before in writing. Imagine my surprise then, when reading James Sallis's Bluebottle a little later that same night, to find the phrase "shank of the afternoon."
I've had this kind of experience before, and it never ceases to amaze me. Like when you learn a new word and suddenly you see it everywhere. But "shank" being used in this fashion has got to be pretty rare, and I wonder what strange cosmic coincidence led to me using this unusual term just when I was reading--quite possibly--the only book in my house to also use the term. On the same day, within less than two hours of each other.
The world is weird, man.