It’s quite ironic that I’m the one sitting in the grammar tree, because, truth be told, I can’t spell, and I have to look up grammar rules all the time. Today, I had no idea which way to spell “vein” in the phrase, “in that vein.” I was editing an essay, and I made an astute suggestion. I went on to offer a similar suggestion in the next paragraph and wanted to lead off with, “In that vein.”
So here’s what I learned:
“In that vane” would mean “in that streak of gold that we’ve just mined from the bottom of the Colorado River.”
“In that vane” could also mean, “Look there’s a cat on our weather vane.”
“In that vain” means, really, nothing because “vain” came from the song by Carly Simon, “You’re so vain.”
The winner is “in that vein” meaning in that similar line of thought—or in that vessel that carries blood away from your heart.