The taxome is the sum of all the described species and higher groups such as genera, families, phyla of all life, or the sum of all valid taxa. The documenting of all this biodiversity is still very incomplete.
Many organisms have already been documented (it is guessed that around 1-2 million species have been described — see Species Inventory in biodiversity article), but probably around nine-tenths of existing species have never been described, and those that have been described may have been redescribed, many times, under different names. Thus, the state of the science of taxonomy (the systematic organization of life) is somewhat confused.
The system of Linnean nomenclature (named after the 18th century Swedish pioneer Carl Linnaeus) is such that, in principle, the correct scientific name of all organisms described could be adjudicated, by means of historical priority. However, the names of many organisms are published in such obscure books and journals that very little of this information is available to most people. Thus, not only do we have little idea how many species there are, but we are even ignorant of the number of supposedly known species that have been described.
However, the situation is not as bad as it is sometimes painted. The sum total of all existing taxonomic and nomenclatural documentation of living things is not large by today's data-rich standards. We know where the books and journals are where species might have been described. We simply need to put in the work to make the text and graphics of species descriptions available in databases, particularly electronic databases. In many groups, species are poorly known, but it is now rare to discover a major undetected phylum or family, so coverage of the kinds of diversity of life is probably good, even if all species are not described. Most of the undiscovered groups are probably reasonably closely related to something we have described. Thus if we could document the existing knowledge, we would have a useful, albeit somewhat pixellated map of the diversity of life.
Just as a sequenced genome of an organism is a map of its DNA, a database documenting the complete taxome would form a map of the described biodiversity of the entire planet. Existing projects are mapping the positions of moons, planets and stars in the universe, as well as the physical geography of our own planet, and the genomes of selected organisms. Projects are now being set up to take advantage of information technology to document and make available the entire body of taxonomy on line. When this information becomes more complete, it should be possible to link this taxome information to all other information about biology.