“Pagan” is used to described any individual who practices a religion within the Contemporary Pagan movement. Religions that fall under this “umbrella” of Contemporary Paganism usually either focus on reviving the pre-Christian beliefs of Europe, North Africa, and the Near East; or they are modern romanticist traditions such as Wicca or Druidry. “Pagan” usually does not describe living traditions such as Hinduism, Shinto, Buddhism, indigenous beliefs, or any other tradition that does not self-describe as Pagan.
Heathenry, as a religion focused on the revival of the pre-Christian beliefs of the ancient Germanic peoples, falls within this “umbrella” of Contemporary Paganism. A Heathen (with a capital H) is an individual who specifically practices Heathenry. Heathenry is not to be confused with Norse Paganism, which can be any Contemporary Pagan religion that focuses on the worship of the Norse gods but does not adhere to the definition of Heathenry as proposed by this website.
As a note, readers may occasionally encounter people who use “heathen” (with a lowercase H) to refer to anyone who is not Christian.