Metonymy

'Field,' by metonymy, is occasionally used as synonymous with 'battle'.

Metonymy does new names impose, And things for things by near relation shews.

...the principle of metonymy is simply to substitute for the plain name of a thing a name or phrase based on something connected with it.

THE KEY CONCEPT IS “metonymy.” This is the act of a word or phrase associated with a concept coming to represent the entirety of said concept. Generally, this means an extension of the original meaning. For example, “city hall” no longer means just the structure, but also the lawmakers who inhabit that structure. In the same way, “dish” started as the physical plate a meal is served on, before people started using it to represent the meal itself.