Gillespie’s chapter argues that the word “algorithm” has become one of the central but most ambiguous terms of digital culture. Rather than treating algorithms as purely technical objects, Gillespie shows that the term operates across different communities: for engineers, an algorithm is a procedural set of steps; for the public, it often appears as an opaque and powerful force; and for social scientists, it becomes a way to discuss the hidden organisation of digital life. The chapter explains that the social significance of algorithms rarely lies only in the code itself, but in the wider sociotechnical assemblage that includes models, data, training sets, applications, designers, corporations and institutional goals. Gillespie therefore distinguishes several meanings of the term: algorithm as a “trick”, meaning a practical procedure for solving a problem; algorithm as synecdoche, where the word stands for an entire technical and social system; algorithm as talisman, used by corporations to claim objectivity, neutrality and legitimacy; and algorithmic as a broader commitment to procedural, automated and quantified forms of knowledge and decision-making. The chapter is especially important because it challenges the assumption that algorithms are neutral mechanisms. Instead, it shows how values enter through choices about what problem is being solved, how data are selected, how goals are operationalised, and how thresholds are tuned. Gillespie concludes that algorithmic systems should be understood as the latest expression of a modern tension between human judgement and procedural systematisation: they may sometimes make decisions more consistent or democratic, but they can also obscure responsibility, reproduce inequality and distance powerful actors from accountability.