Today, we sometimes talk about a Hubble constant, which is the rate at which the Universe currently expands. It is a constant in the sense that today, its value everywhere in space is the same. But actually the Hubble parameter is not constant. It changes with time. Earlier in the Universe, when things were denser and gravitational effects were stronger, the Universe expanded far more rapidly than it does today.
Calling it constant but not really a constant. Weird.
