The research into the perception of early signals, the so-called weak signals, started in the field of strategic planning in the 1970s. Soon, research dispersed into new, specialized fields, such as foresight, sense-making, and entrepreneurial alertness. Each field used different terms for weak signals and framed the research in its own theoretical and methodological basis, which led to many different descriptions of weak signals. To put a stop to the growing number of definitions, this paper presents a contrarian approach. The usual simple combinations are likely to omit relevant meaning when underlying definitions only partially overlap. Therefore, his paper used a three-step approach including cluster analysis to unify 68 reviewed definitions into one. Cluster analysis includes more meaning by summarizing data. The analysis resulted in the defining of weakness in terms of distance to a perceiver's frame of reference. Distance explains the difficulty of perceiving weak signals more clearly than keywords like novel, ambiguous, or ill-defined. Distance also helps to quantify the amount of weakness in signals. Our approach may help others to find clarity and retain meaning when constructs are fuzzy. Defining weakness in distance opens up comparative studies between signals of various levels of weakness.@en