Ontologies are commonly used as a strategy for knowledge representation. However, they are still

presenting limitations to model domains that require broad forms of temporal reasoning. This study is part of

the Onto-mQoL project and was motivated by the real need to extend static ontologies with diverse time

concepts, relations and properties, which go beyond the commonly used Allen´s Interval Algebra. Therefore,

we use the n-ary relations as the basis for temporal structures, which minimally modify the original ontology,

and extend these structures with a generic set of time concepts (moments and intervals), time concept

properties (precise and uncertain), time relations (interval-interval, interval-moment, and moment-moment),

and time relation properties (qualitative and quantitative). We divided the scientific contribution of this study

into three parts. Firstly, we present the ontological temporal model (classes and properties) and how it is

integrated into static ontologies. Secondly, we discuss the creation of axioms that give the semantics for

precise temporal elements. Finally, as our main contribution, these ideas are extended with axioms for

uncertain time. All these elements follow the Ontology Web Language (OWL) standards, so this proposal is

still compatible with the main ontology editors and reasoners currently available. A case example

demonstrates the use of this approach in the nutrition assessment domain.