Quinarianism is a term that refers to the belief that all things in nature are created in groups of five. However, there are a few other synonyms that can be used in place of quinarianism. One synonym could be pentamerous, which means arranged in groups of five. Another synonym that could be used is quintuplicate, which also refers to five identical or similar things. Additionally, quinquepartite is another synonym that can be used to describe the concept of five equal parts or divisions. Overall, these synonyms can be used interchangeably with quinarianism to describe the belief in the importance of the number five in nature.