Genealogy is broadly defined as the study and tracing of family lineages and history. Theoretically, the history of an individual's family can span across thousands of years and be linked to the history of even a larger number of other families. In reality, and for practical purposes, families tend to limit the circle of their "family", usualy as a way of establishing, encompassing and limiting "Us" and "Not Us" categories for the purposes of social interaction and exchange. Laws, customs, folkways, and mores attempt to define the rules by which such groups and sub-groups are established and maintained. While the genealogical process is continuous, formal and informal geneological discourses attempt to describe the shape of the outcomes of the process, at a particular time in history.
The construction of genealogies is practiced popularly now among many people's of the world, leading to books and other types of publications. From conversations I have had about this curiosity and hobby, I have concluded that genealogical research is something that many people are interested in and would like to pursue. But, only some actually engage in it and carry it to a conclusion. Doing it right involves a lot of work, with not so easily accessible historical records. I have also found that the uses of genealogical research are wider than those I have been familiar with from my own research and reading.
The word "genealogy" may sometimes refer only to the sciences related to the tracing of biological and genetic relationships among humans as well as other plant, animal, insect, bird, and other life forms. The term pedigree, often used as a synonym for genealogy, is also an important, marketable characteristic of dogs, cats, and horses for instance. Similarly, plants and trees have genealogies.
The larger dictionaries list several definitions for the meaning of "genealogy". The idea of descent is common to all of them. Descent would thus seem to be the key component of the dictionary meaning for "genealogy".
It is a matter of curiosity, perhaps only to new learners of English, that folk speech and popular literary use, e.g. on the internet, refer to the discovery of "family trees" as the intended outcome of genealogical searches. We all know that in nature, trees ascend from the ground up. Typically, trees do not present a picture of descent. I have always found this misleading contradiction rather disturbing.
The "tree" diagram image for descent relationships is in fact useful, because trees (and vines which need some other solid surface to grow on) have stems and branches which in turn have more branches. Unlike individual living trees and vines, however, family "trees" can grow from theoretically limitless origins to similarly unknown ends. It is useful to keep in mind that the fit of the tree image for purpose of understanding genealogical relationships works only for imaginary trees which represent descent from the past to the present, and from one form to another. Rivers, streams, and roads also have a main body and branch bodies. In any case, "genealogical chart" seems to be a better description of the diagrammed outcome of genealogical researches.
The recent development of the popular practice of genealogical knowledge has some of the same goals as those of modern ethnographers who, from about the middle of the 19th century, have developed very sophisticated kinds of discourses related to kinship and genealogical research methods: it is to record and establish the familial kinship and ancestry of individuals, filling in gaps in available beliefs, and correcting erroneous beliefs if such have prevailed. British, European, and US social, cultural and other types of anthropologists who have a history of doing elaborate kinds of field research among non Euro-American peoples have made constructions of models of "society" as it existed in the societies which they studied. The models of "society" in almost all cases of their early research were based on ideas about kinship and genealogy. Ethnographers had made knowledge of certain techniques of genealogical research and description a basic competency required of their students. Most undergraduate level anthropology text books even now contain a chapter on kinship and genealogical relationships.
In general also, the anthropological sciences related to this matter of common human interest has remained a separate field of study and discipline from the popular field that has emerged as a matter of widespread curiosity and activities, for instance, in US culture. The rise in this popular interest motivating many people, and organized groups, to research their own genealogies, "family trees", and so forth, it is said to be a consequence of the popularity of Roots, a novel by Alex Haley published in 1976, and the subsequent movie.