Query is a key component of the information retrieval process. It is a complex, multi‐faceted and vague term that has been subject to a broad range of definitions. Both user‐centred and system‐centred models of information retrieval stress the importance and role of query in successful information retrieval experience. However, there is a lack of a rich, consistent and well‐defined terminology for query. This paper proposes a new faceted classification of query in the context of interactive information retrieval and conceptualizes the many facets, aspects, characteristics and features of query based on a comprehensive analysis of the literature. The resulting classification provides a useful framework for understanding query and its various aspects for research and learning purposes. Specifically, it provides a conceptual foundation for operationalizing the many aspects and facets of query as variables for research purposes.