Some of my favorite stories are actually the etymologies of words, especially those that display the oddly associative nature of human thinking.
The word “muscle,” for example, comes from the Latin word musculus, which means, “little mouse.” Quick, flex your bicep. Looks a bit like a scurrying mouse, no? This is also the origin of the Sanskrit word for testicle (muska) from which we get “musk.” Because a musk gland resembles a scrotum, which itself resembles a mouse.
Speaking of balls, the word “avocado” famously derives from the Nahuatl ahuakatl, meaning “testicle,” while the actual word “testicle” is thought to come from either the Latin testi, meaning “witness” (from which we get both “testify” and “testimony”) or testa, meaning “pot” or “shell,” (from which we get both “test” and “tortoise.”)
On a more romantic note, the word “engagement” comes from the French gage, meaning something thrown down by knight as a pledge of protection, often a glove. (This is also where we get the word “mortgage,” which somewhat less romantically means “dead pledge.”) All that romance might lead to fornication, which comes from the Latin fornix, meaning, “arch.” Prostitutes, apparently, liked to hang out under domed structures.
There is also an arch-shaped structure in the brain called the fornix, at the ends of which lie two round bundles of neurons called the mammillary bodies. Five bucks if you can guess what the scientist who named those thought they looked like.