quenched fractions
they discovered that the presence of huge galaxies among their fossil structures didn't necessarily indicate stability – kind of like having one more energetic kid join an otherwise quiet classroom doesn't mean everyone's just sitting down quietly! In fact, both "rested" fossils and active non-fossils had some of their little subgroups buzzing around.
Technical definition
The proportion of galaxies within a population that have ceased to form new stars, often due to depletion of gas fuel.