My first guess (and probably the first guess of many of the old school nerds) was that the MS Word codename is from Opus the penguin from Berkeley Breathed's Bloom County comic strip and that seems to be correct.

High five for anyone who still remembers the brief Bill the Gates arc in the comic or the Banana Computer parody ad of Apple starring Gene Simmons (https://computerhistory.org/blog/the-banana-junior-6000-comp... , about halfway down the page).