Based on form:
* Prose: This is the most common antonym, referring to ordinary language without metrical structure or rhyme.
* Nonfiction: This focuses on factual writing as opposed to the imaginative and often emotional nature of poetry.
Based on content:
* Technical writing: This is focused on conveying specific information or instructions, the opposite of the often evocative and symbolic language of poetry.
* Plain language: This emphasizes simple, clear communication, as opposed to the metaphorical and sometimes complex language of poetry.
Based on purpose:
* Practical writing: This refers to writing that has a specific purpose, such as a report or a manual, as opposed to poetry which often explores emotions and ideas.
Ultimately, the best antonym for "poetry" will depend on the specific context in which you are using it.