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The term DLA for damped Lyman alpha absorber is used for whatever astronomical object produces a damped absorption line (i.e., with a Lorentzian profile) in the Lyman-alpha forest evident in the spectrum of a quasar. The quasar's electromagnetic radiation (EMR) travels over cosmological distance and time, and the spectral signature of absorption at various redshifts provides a means of identifying the presence of objects that the EMR has passed through. The damped line broadening provides clues to the amount of hydrogen in the object that the EMR is passing through, a clue to its size and mass. The DLAs are necessarily clouds of hydrogen, presumed to be within galaxies, thus the Lyman alpha forest and the DLAs are indications of distant galaxies, with the redshifts providing a distance and lookback time through Hubble's law.