I usually hear the term "kerolox" in the context of methalox vs kerolox discussions (and hydrolox, but I often hear that just called "hydrogen"). Methalox is relatively new, at least as a front-running contender, so the numerical majority of these discussions (and by extension use of the terms and consensus around the terms) probably did happen in the last 10 years, even though the roots go much further back.

It's the language barrier between online forums and "the real world". Increasingly blurred, but still present.

At least several decades, into the Space Shuttle era. But maybe not Apollo era.