Seems like every company that's preparing to spin off part of its operations uses "SpinCo" as a placeholder for the name of the spun-off company. Way back in 2016 when I worked at Yahoo, SpinCo was going to be a holding company for their investments in Alibaba, the Chinese tech company. (The Yahoo corporation instead sold all their OTHER assets to Verizon, including the Yahoo name and trademarks, and changed their name to Altaba.)
More recently, in the merger plan for Kroger and Albertsons, SpinCo was going to be a company that owned the stores they were going to divest in order to get merger approval. (They later altered the plan to instead sell the stores to a grocery wholesaler named C&S, but it became moot when the merger effort was discontinued.)
Those are just two examples I could think of off the top of my head - I know there have been others (but this is something that's hard to search for!).