The C-ODO library currently contains 8 native ontologies, and imports or uses several others, either for design purposes (DOLCE, cDnS, etc.), or for extending their scope (owlodm, OMV, oQual, SKOS, NeOn networked ontology model). odArgumentation.owl is the module that provides a vocabulary to encode argumentation structures and activities that allow multiple agents to take decisions in the ontology lifecycle.. C-ODO is an ontology for ontology design, to be used as a set of social requirements for NeOn methodologies and tools. The key notion is 'ontology project', which is assumed to be made up of knowledge-level ('epistemic') workflows, which on their turn contain 'argumentation structures' and 'design rationales' that motivate 'design solutions' taken from a 'choice space' generated by 'design patterns' over 'ontology elements'. Appropriate roles (e.g. 'knowledge product', 'knowledge creator') and tasks (e.g. functionalities like 'selection', 'importing', etc.) are used by project, workflow, and rationale schemas. Situation classes ('ontology project execution', 'epistemic workflow enactment', 'argumentation situation', 'design making', 'design solution') are introduced in order to reason on the actual occurrences of those schemas. Moreover, ontology objects and other information objects used during the ontology lifecycle, together with the design operations and the designer agents, are framed by those situations if they comply to the roles and tasks used by the schemas. Types of projects, workflows, argumentation, rationales, patterns, etc. are also introduced in C-ODO. The schema-situation approach is an architectural design pattern that is wholly axiomatized in the cDnS ontology (http://www.loa-cnr.it/ontologies/cDnS.owl). It allows to talk of contexts (or methods, plans, etc.) in the same domain as the actual situations (executions, observations, etc.) that exemplify those contexts. More generally, the ontology design ontology uses the following patterns: - the DnS content pattern (http://www.loa-cnr.it/ontologies/ExtendedDnS.owl) has been used throughout, and the following sub-patterns have been used: a) descriptions and concepts depend on existential axioms only when they involve 'descriptive' entities b) descriptions are constrained wrt a given situation class SC c) concepts are constrained wrt a given entity class EC d) SC are defined by requiring that some entity from EC is in their setting. - the collections pattern (http://www.loa-cnr.it/ontologies/ExtendedDnS.owl), and the following sub-patterns have been used: a) collections have any entities as members b) collections are covered or characterized by concepts c) collections are unified by descriptions that use or define those concepts. -the plans pattern (http://www.loa-cnr.it/ontologies/Plans.owl): a) plans use tasks, roles, and parameters b) plans have a main goal as a proper part c) plans are 'executed' within plan executions by agents playing roles in order to perform the tasks used by the plan d) plan executions start from certain situations ('preconditions') and result in certain situations ('postconditions'). Postconditions can be compliant or not to the expected goal. ontology design argumentation ontology 41 1 A role taken within an argumentation situation, e.g. an axiom that is 'motivated' or 'agreed upon' within a design making. 1 A schema or frame for argumentation primitives, e.g. agree/disagree, motivated claim, etc. An argumentation structure for ontology design is supposed to include a rationale that is used to argue about a design choice. A collaboration workflow focused on arguing on one or more design choices. As inspired by van Eemeren and Grootendorst (2004), an argumentation session includes four complext task types: choice-confrontation, rationale-declaration, dialectic-rule, argument-resolution. Argumentation rules can be composed of any set of tasks defined in an argumentation-structure. An argumentation task is a complex task to be accomplished within an argumentation situation. Four typical classes of argumentation tasks have been singled out: choice-confrontation, rationale-declaration, dialectic-rule, argument-resolution. An agent can argue about any aspect of ontology design. Typical, agents argue about a design solution (situation) or about an information object that is implemented or used in ontology design. It could be assumed that in case an agent argues about an ontology element, she is actually arguing about a design solution that is a setting for that element. This property is typically asserted within an argumentation situation.