A synecdoche is a figure of speech or expression used to denote and in some case define a person or a whole object. Effectively it works as a de facto name, often including a characteristic of the object. The usage is bordering on slang, but can be efficient when it's used as a briefer version of a formal usage like a long name or technical/scientific taxonomic descriptor. Some synecdoches are in fact acronyms turned into 'names'.