  We assume that substances in the world are represented by two types of
concepts, namely substance concepts and classification concepts, the former
instrumental to (visual) perception, the latter to (language based)
classification. Based on this distinction, we introduce a general methodology
for building lexico-semantic hierarchies of substance concepts, where nodes are
annotated with the media, e.g.,videos or photos, from which substance concepts
are extracted, and are associated with the corresponding classification
concepts. The methodology is based on Ranganathan's original faceted approach,
contextualized to the problem of classifying substance concepts. The key
novelty is that the hierarchy is built exploiting the visual properties of
substance concepts, while the linguistically defined properties of
classification concepts are only used to describe substance concepts. The
validity of the approach is exemplified by providing some highlights of an
ongoing project whose goal is to build a large scale multimedia multilingual
concept hierarchy.
