period-luminosity relation: Meaning and Definition of

pe'ri•od-lu•mi•nos'i•ty rela"tion

Pronunciation: (pēr'ē-ud-l"mu-nos'i-tē), [key]
— Astron. Astron.
  1. the relationship between the period of light variation and of the absolute magnitude of Cepheid variable stars.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.