A Microsoft file hosting and synchronization service.
You can use the "Free up space" feature to ensure that only the latest version exists in the cloud since it is the only version. That's just a workaround, though, and not what you really want.
I'm not sure how this would have been a work around. It would appear that upon booting up the less frequently used laptop that still contained an old version of the document, Onedrive uploaded that old version and removed all trace of the latest version from the cloud.
Then when I booted up my regular, daily use laptop, Onedrive downloaded that old document from the cloud and erased the current one that still existed in the laptop.
So I appear to have gone from having the latest version on one laptop as well as in cloud, along with old version on less used laptop, to old version on both laptops and in cloud and all trace of newer version removed.