What prefix signifies the concept of being between?

The prefix that signifies the concept of being between is "Inter-." This prefix is derived from Latin, meaning "among" or "between." It is commonly used in various medical and scientific terms to indicate relationships or positions that are situated in the space between entities. For example, the term "intercellular" refers to the space and interactions between cells, highlighting relationships that occur in the spaces separating individual cells.

In contrast, "Mid-" typically refers to the middle or center of something, but it doesn't specifically denote the concept of "between." The prefix "Exo-" means external or outside, often used in terms like "exoskeleton," which refers to a structure outside of an organism. "Para-" generally indicates a position that is alongside or adjacent, but it does not capture the essence of being positioned in between two entities as effectively as "Inter-" does. Thus, "Inter-" is the most accurate choice for conveying the idea of being between.