Who uses it: Emergency-room doctors and neurologists
What it means: An injury to opposite sides of the brain, caused by the double impact of a head hitting something, then being thrown forward to hit something else. Think of a car being hit from behind, then slamming into the car in front of it.
How you can use it: To describe something that provides a double effect.
I'm sorry that I know this word, because I learned it from my cousin Sheila, through her personal experience.
It popped immediately into my head last night, when I -- inevitably -- lost my balance, fell on my rear, and cracked the back of my head on the ice. I did not give myself a contrecoup injury, and I don't think I injured my brain at all -- just the back of my head, which now has a rather disgusting bump on it.
As for the fall, it happened while I was jumping on the ice, so I can't be too embarrassed about it. You have to be able to jump two feet on the ice in order to pass Level One of the Basic Skills class. Polly, my instructor, said, "Imagine you're a kid jumping off your parents' sofa," and I imagined it a little too vividly, cracked head and all.
At least, unlike my sister Peggy on a similar occasion (jumping off the sofa, not learning to skate), I did not put my front teeth through my upper lip.
I'll miss next week's class -- not because of last night's injury, but because I have to be in Boston -- so I need to get back to the rink sometime before this week ends.