Comoving distance
Think of two ants on the surface of an expanding balloon. One ant starts moving towards another, but the balloon itself is also expanding. After a long time the balloon starts expanding more slowly. Eventually one ant reaches another. That's like photons in our universe. Some of the light from the stars you see at night traveled for billions of years to reach your eye. Surprisingly, it started very close to where you were (or the atoms of which your body consists), but just could not keep up with the universe expansion. Of course, if something else started out very close to where you were, but was not traveling toward you, it would be very far away from you now because of the expansion.