metonym

A word that names an object from a single characteristic of it or of a closely related object; a word used in metonymy.

Calling a government a "city hall" is using a metonym.

...to say that "New York was thrown into a state of great excitement," when we mean the inhabitants of New York, is technically to use the metonym of putting "the container for the thing contained."

A concept, idea, or word used to represent, typify, or stand in for a broader set of ideas.

See also: symbol, model, microcosm, archetype, exemplar, proxy

Chapter 1, using the railway as a metonym, explored the relationship between past and present, and argued that diachronic, or historical, time was dissolved in the proliferation of present moments, or synchronic time.