1. A method comprising: accessing a corpus stored in one or more tangible media, the corpus comprising a plurality of terms; performing the following for each term of one or more terms of the plurality of terms to yield a plurality of parent-child relationships: identifying one or more parent terms of the each term according to directional affinity, the plurality of terms comprising the one or more parent terms; and establishing one or more parent-child relationships from the one or more parent terms and the each term; and automatically generating a hierarchical graph from the plurality of parent-child relationships.