‘Active ageing’ is a topic of increasing attention in scientific and policy discussions on ageing, yet there is no consensus on its actual meaning. The current paper proposes a detailed classification of various definitions that have been used since its introduction. These definitions are subjected to critical investigation, and subtle differences with regard to such terms as ‘healthy ageing’ and ‘productive ageing’ are clarified. Bearing the hazards of previous definitions in mind, a comprehensive strategy is initiated. Given that earlier definitions have tended to exclude frail older adults, this strategy pays particular attention to the translation of the active-ageing concept to situations of dependency by centring on three key principles: fostering adaptability, supporting the maintenance of emotionally close relationships and removing structural barriers related to age or dependency.