a thing of one type leads to a thing of an entirely different type, when viewed at a different scale.
a phenomenon whereby larger entities arise through interactions among smaller or simpler entities such that the larger entities exhibit properties the smaller/simpler entities do not exhibit.
For example, string a bunch of musical notes together... what do you get? Just a bunch of notes? No, you get a melody. Put a bunch of letters together and (if you're good at it) you might get a bunch of words. Put a bunch of words together, you might get a sentence. Put a bunch of sentences together in just the right way and you get a best-selling novel. Put them together in the wrong way and you end up in jail for blackmail. (It's an easy mistake to make. Take a wrong turn along the way and you could end up there too.)
What else emerges? Well "life" is a pretty big example of emergence. Molecules smash together in such a way that they continue to smash together in that same way. What is life? Is fire alive? Is fire similar to life? Is life similar to fire? Is life just a chemical reaction? Or something more?
Emergence shows us that something can be "just" the components and also be something more, all at once.