The document discusses taxonomy, which is defined as a subject-based classification that arranges terms in a controlled vocabulary to group related terms together and make information easier to find. There are four main types of taxonomy architectures: flat, hierarchical, faceted, and network. Hierarchical taxonomies structure content into at least two levels with bi-directional hierarchies. Facet taxonomies describe properties or values of a topic through different attributes and facet values. Network taxonomies organize content into both hierarchical and associative categories, allowing any two nodes to be linked. The document also discusses browse vs. formal taxonomies, strengths and weaknesses of each, and examples of taxonomy/text analytics software and vendors.