I learned about conkers when I was very young and read the Hitchhikers Guide for the first time... "We bust our way into a megafreighter I still don't know how, marched on to the bridge waving toy pistols and demanded conkers. A wilder thing I have not known. Lost me a year's pocket money. For what? Conkers. The captain was this really amazing guy, Yooden Vranx," said Zaphod. "He gave us food, booze - stuff from real…
Would the word not be in a dictionary?
The big honking dictionary on a pedestal at the high school library probably would have had it, and if that was not enlightening then the library in the closest city that we visited monthly would have good encyclopedias that probably would have described it. But I don't remember the conkers reference catching my imagination, and probably wrote it off as a silly made-up sci-fi word.