Me: So get this. It’s called a “tank top” because a long time ago we used to call swimming pools “swimming tanks,” and people thought that the shirt looked like a “swimming tank top“—that is, a swimsuit top! So we have an article of clothing whose name everyone recognizes and uses, but which is named after an obsolete term for a swimming pool!
Her: Whatever.
I’m away from all useful resources, but “tank” is an (East) Indian word, meaning pond or reservoir, IIRC. And “tank” as in Sherman/Abrams/Panzerkampfwagen is from a usage of “tank” meaning secret or hidden — it was the code word for the secret weapon of WWI.
All of this, of course, depends on my decrepit memory.
Whatever.
So I’ve been wasting my time looking for tank-bottom themed erotica?