stepwife
n.— «In regard to what word your sister should use to describe her former husband’s new spouse, we have heard a few terms to describe that relationship: You used one of them, “wife-in-law.” We have also heard the term “stepwife,” but neither seems quite appropriate, the reason being that both use the term “wife” as the root word, and the relationship in question has nothing to do with being a wife to each other, or even that both women have been a wife to the same man.» —“Here’s one way to introduce your ex’s current spouse” by Jann Blackstone-Ford, Sharyl Jupe Mercury News (San Jose, California) June 15, 2005. (source: Double-Tongued Dictionary)
Further reading
If you speak a second or third language, you may remember the first time you dreamed in that new tongue. But does this milestone mean you’re actually fluent? And a couple’s dispute over the word regret: Say you wish you’d been able...