In contemporary metaphysical discussions the word "emergence" and its variants play a big part.
It often appears in the context of the mind-body problem. The mind (or intentionality, or consciousness, or whatever you may call the intangible subjective aspect of our reality) is said to have "emerged" at a certain moment in evolution, and to recapitulate this by "emerging" again at a certain moment in embryology.
I think there is an element of word magic involved. We lessen the mystery of something by having a good word for it.
IIRC, Samuel Alexander built an impressive metaphysical structure around this word magic. Matter, he said, emerged from space, then life from matter, then mind from life, like a growing ziggurat.
I bring this up because I came across an intriguing discussion of the ambiguity of the word in my recent web surfing. Here is a link.
It turns out that was written a year ago but, hey, that's an eyeblink for the chronology of the development of philosophy.
The blogger in question uses the example of the relationship between a battalion and its soldiers as a paradigm for confusions over "emergence." The whole point of military discipline, after all, is that a battalion will act as one entity, not as many. And surely a historian may well need to talk of the battalion as a whole. So, is a battalion an emergent? If so, what has emerged and does this have anything to do with Alexander's Big Picture?
The blogger at Powers, Capacities, and Dispositions writes that there are various equivocations about the battalion and the soldiers that he doesn't want to hear!
Not: “Well, battalions exist alright, but what they are is a plurality of soldiers.” Not: “Battalions aren’t anything in addition to a plurality of soldiers since what a battalion is is a plurality of soldiers duly arranged.” And for sure not: “Battalions are the same thing as a plurality of soldiers, but I can’t talk about the behavior of a battalion unless I help myself to the macro-level terminology, so I will, and it follows from this that I am not a reductionist.”
This blogger's point is that although he is happy with the notion that the battalion is a distinct thing, the word "emergence" should be reserved for something more than just such distinctiveness. It is more than the negation of methodological reductionism. What is the "more"? Ah, that is the issue, and one of metaphysics not of semantics.