TaxID

NCBI TaxIDs are stable unique identifiers for each taxon (for a species, a family, an order, or any other group) in NCBI's taxonomy database.
sequence similarity searches against sequence collections can yield hits with multiple taxIDs (separated by semicolons). BlobTools create only parses the first taxID.
for more information, please refer to the NCBI Handbook: Chapter 4 "The Taxonomy Project" and the NCBI Handbook: Glossary