Thankyou !! I appreciate the input 🙏**I'm not a cellologist nor a grammar expert. Take the following with a grain or 2 of salt.
While the nomenclature / # references have changed over the years depending on what you read, I don't think the actual size has change since before WWII. Maybe ever.
the one in your pic is a standard sized D cell albeit vintage.
That's all I could come up with.