noun. A device bigger or smaller than a breadbox that's quite handy, perhaps even essential, in detecting jackassy behavior and lifeforms.
Real citation: “Captain Atom. I got my hands on some Armageddon Annuals from 1991 and really got the feeling that Monarch coulda been somebody. He could bena contendah! But, they made him Hawk instead. Hawk, a character on the same level as Guy Gardner on the Jackassometer. But, who knows, maybe they'll do a hypertime where Monarch is revealed to be Captain Atom.”
(Justin M. Campbell, Jan. 30, 2004, http://forum.newsarama.com/archive/index.php/t-8601.html)
Made-up citation: "Items that are useful in cities: smoothie maker, stun gun, portable jackassometer, cruelty-free ball-waxer, pocket-size weapon of mass destruction."