In his seminal book, Xenology, Robert Freitas defined xenology as "the scientific study of all aspects of extraterrestrial life, intelligence, and civilization."

Compared to the restrictive definition the Wikipedia gives, Freitas definition is far better. Still, it would be useful to expand it to also include the relationships between extraterrestrials and humans, especially the ones that are already present here on Earth, and probably have been for a long time.

Hence, the need for a new definition. Let us define xenology as the scientific study of all aspects of extraterrestrial life, intelligence and civilization, both on and off-planet, including the already existing relationships between humans and those extraterrestrial groups who are and have been present on Earth.

The relationship between anthropology and xenology

The field of xenology can be modeled after the field of anthropology, and use its methodologies, mutatis mutandis. It can be divided in the following subfields of study:

It should be pointed out that we, humankind, have already reached a point where our biologicial and technological evolution can start merging, establishing a new type of participative evolution.

 Source: Manuel Lamiroy, Introduction to Xenology, 2020.