While scientific terms lack the stability of physical objects, they are generally far more stable than the various meanings associated with them. As a consequence, they tend to carry older conceptions alongside those more recently acquired, thereby exerting an effective drag against conceptual change. I illustrate this claim with an analysis of the shifting meanings of the term genome, originally used to refer to a collectivity of genes, but more recently to an organism’s complement of DNA. While genes were originally (...) regarded as effectively autonomous formal agents, and DNA as collections of genes, contemporary research suggests that an organism’s DNA constitutes a far more complex system designed to adapt and respond to the environment in which it finds itself. (shrink)