A document taxonomy alignment system and method, relying on document glosses and utilizing a soft ontology expansion. An all-new hierarchical leaf node can be created expressly for the purpose of better aligning the plurality of document taxonomies in question. A small but valuable subset of the nodes created by soft ontology expansion turn out to capture some otherwise unmappable taxonomy nodes, and thereby have the effect of classifying the documents better than would any pre-existing node in any one of those taxonomies.