Context: In the software product line domain, the concept of variability is well recognized. However, variability in the context of software architecture still seems to be poorly understood. Objective: In this paper, we aim at contributing to the development of a basic understanding of the notion of variability in the software architecture domain, beyond the idea of product lines. Method: We perform a preliminary exploratory study which consists of two parts: an expert survey among 11 subjects,

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... and a mini focus group with 4 participants. For both parts, we collect and analyze mostly qualitative data. Results: Our observations indicate that there seems to be no common understanding of "variability" in the context of software architecture. On the other hand, some challenges related to variability in software architecture are similar to challenges identified in the product line domain. Conclusions: Variability in software architecture might require more theoretical foundations in order to establish "variability" as an architectural key concept and first-class quality attribute.