On the ontology of part-whole relations in Zulu language and culture C. Maria KEET a,1 and Langa KHUMALO b a University of Cape Town, South Africa b University of KwaZulu-Natal, South Africa Abstract. Parthood and attendant part-whole relations enjoy interest in ontology authoring for various subject domains, as well as in, e.g., NLP to understand text. The list of common part-whole relations is occasionally slightly modified for lan- guages other than English. For isiZulu, it was shown that there are not always 1:1 mappings and, moreover, dictionaries list many more translations for parthood and part-whole relations. This complicates selecting the semantically appropriate ones for localising ontologies or aligning local ontologies to other ones. It also raises the question whether the ‘common’ part-whole relations are really that common. We aim to investigate the extant part-whole relations in isiZulu and determine their ontological status. We harvested a lexicon of 81 terms from dictionaries, which was reduced to 31 through several iterations of refinement, of which 13 were formalised and aligned to well-known part-whole relations. It showed that in some cases dis- tinctions are made—and for which words exist—that have not been included before in part-whole relations, yet in other cases it is more coarse-grained; e.g., a parthood for portions of cloth, for objects properly contained in the mouth, and for regions with a part-region that has a fiat boundary and objects located in it. Keywords. Mereology, Meronymy, IsiZulu 1. Introduction Parthood, and, more generally, part-whole relations, are well-known to play a central role in ontology authoring across multiple subject domains and have been investigated both in philosophy and ontology engineering. Here, we refer to both mereological theo- ries proper starting from ground mereology (e.g. [34]) and the language and cognition- inspired lists and taxonomies that took off since Winston et al’s paper [37] that is typi- cally of greater interest for domain ontology developers than the properties of parthood. These common relations include, among others, involvement as a parthood between pro- cesses, containment as a parthood of regions occupied by objects, and membership of objects or the roles they play in a collective. They are just as relevant for localisation and internationalisation of ontologies; e.g., to localise SNOMED CT [31] for its use with electronic health record systems such as OpenMRS [27] that is relatively popular in Sub-Saharan Africa, and to describe more precisely (Southern African) architecture [11]. Such ontology-driven information systems in a local language can assist with, e.g., gen- 1 Department of Computer Science, University of Cape Town, South Africa, mkeet@cs.uct.ac.za.