What does the prefix "ec/ecto" signify?

The prefix "ec" or "ecto" signifies "outside." It is derived from Greek, where "ek" means "out" or "out of," and "ecto" also indicates an exterior position. This prefix is used in various contexts in biology and medicine, such as in terms like "ectoderm," which refers to the outer layer of cells in an embryo, and "ectopic," meaning something that is located outside of its normal position. Thus, when the prefix is used, it conveys the concept of being on the exterior or outer side of something, making "outside" the correct definition.