I found this oddball word in an article from The Smithsonian Magazine, which is an online, subscription only magazine. An interrobang is a fairly new punctuation mark, coined in 1967, meaning an exclamation point inside of a question mark.
“The mark gets its name from the punctuation that it is intended to combine. Interro is from “interrogation point,” the technical name for the question mark, and bang which is printers’ slang for the exclamation point. The interrobang is not commonly used-its absence from standard keyboards can explain its paucity in print.”