Allometric is a term used in biology that describes the proportional relationship between different parts or features of an organism. Some synonyms for allometric include the words proportional, scalable, and relative. Other words that may be used to describe this relationship include the terms dynamic, variable, and size-dependent. These words describe the relationship between different parts of an organism or system and how they change as the organism grows or evolves. While some synonyms are more commonly used than others, they can all be used to paint a picture of the complex relationships that exist within biological systems.