Which prefix signifies "equal"?

The prefix "iso-" is derived from the Greek word "isos," which means "equal" or "identical." This prefix is commonly used in various scientific and medical contexts to indicate that two or more entities are the same in quantity, quality, or nature. For instance, in terms like "isometric," it refers to equal measurement, and "isotonic" refers to equal tension or pressure in a solution compared to another.

The other prefixes have different meanings; "dys-" usually indicates difficulty or abnormality, "mal-" refers to bad or poor condition, and "hetero-" implies difference or otherness. These prefixes are not related to the concept of equality, which further emphasizes that "iso-" is the correct choice for indicating "equal."