tridem
n.— «The non-steering wheels in front of the “bogies” are called “pusher axles” and wheels behind the “bogies” are called “tag axles.” They are single wheels. And they are for wieght regulations. If there are three drive axles in a row they are called a “tridem” instead of “bogie.”» —“Fabulous Peterbilt rigids. Biglorryblog shows the pride of Paccar!” Big Lorry Blog (United Kingdom) Feb. 20, 2008. (source: Double-Tongued Dictionary)
Further reading
In our earlier conversation about the term clam, which musicians use to refer to a “missed note” or “musical mistake,” Martha misspoke and said a similar term was used in rowing and sculling. Actually, as many listeners...
“What has a head like a cat, feet like a cat, a tail like a cat, but isn’t a cat?” Answer: a kitten! A 1948 children’s joke book has lots of these to share with kids. Plus: an easy explanation for the difference between...