You know, that's a good point you raise, I used the same term a few days back on ET and looked it up on Merriam & Websters before (but still carried on with using it) because I thought it didn't carry the extra meaning that it does in French. The original meaning exists in both French and English, but in French we also use the term to define a relationship of equilibrium (and joy if applied to humans). Does Spanish have that extra meaning too?