The term blended learning is used frequently, but there is ambiguity about what is meant. What do we mean by blended learning? What, how and why are we blending? In this paper different definitions, models and conceptualizations of blended learning and their implications are discussed. Inclusive definitions and models, and diverse conceptualizations, mean that essentially all types of education that include some aspect of face-to-face learning and online learning is described as blended learning in the literature. Blended learning has become an umbrella term. Blended learning is also used to describe other blends, such as combining different instructional methods, pedagogical approaches and technologies, although these blends are not aligned with influential blended learning definitions. Since blended learning has many meanings, it is important that researchers and practitioners carefully explain what blended learning means to them. It is also suggested that alternative, more descriptive terms, could be used as a complement or replacement to blended learning.