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The prefixes ex – and exo – mean “out of” and can be found in various everyday words. In addition, they appear frequently in medical terminology. Some of the most common words that include these prefixes are: exfoliant, exothermic, and exotic, among others.
Meaning of the prefixes ex – and exo –
The prefix ex – derives from the Latin, and probably from the Greek ek- and this, in turn, from the Indo-European eghs-. It means “outside”, “exterior”, “external”. It is considered as a separable prefix, that is, it can be written together with or separated from the word. Is used for:
- Indicate that something is no longer what it was. In these cases it is written separately. For example: ex-boyfriend, ex-president, ex-wife.
- Point out that something is “outside”, “far from”, “beyond” or “external to”. In this case it is written together with the rest of the word. For example: extracurricular, exodus.
The prefix exo – comes from the Greek and also means “outside”, “external”, “from the outside”, “far from”. It is very common in sciences such as biology, anatomy, and medicine, as it is used to name various conditions, organ positions, and physiological processes.
Examples of words with the prefixes ex – and ex o-
Some of the most frequent examples of words that include the prefixes ex – and exo – are:
| Term | Meaning |
| exoskeleton | Skeleton or strong structure that is outside the body and protects or supports an organism. |
| exophthalmos | It is an abnormal bulging of the eyeballs outward. It is related to hyperthyroidism and Graves’ disease. |
| Exfoliation | It is the process of removing cells or scales from the outer surface of a tissue, usually the skin. |
| Excoriation | The excoriation is a wound in the outer layer of the skin. It could be an abrasion, scratch, or sore. |
| exergonic | It is a biochemical process that involves the release of energy into the environment. These types of reactions occur spontaneously. Cellular respiration is an example of an exergonic reaction that occurs within our cells. |
| exocarp | It is the outermost layer of a ripe fruit, which works as protection. It can be very fine, like peach skin; thicker, like the peel of an orange; and also hard, like the shell of the coconut. |
| exocrine | It is the secretion of a substance that is produced externally, such as secretions from the sweat glands (sweat) or salivary glands (saliva). |
| exocytosis | It is a process that moves substances from the inside of a cell to the outside. |
| exoderm | It is the outer germ layer that makes up the skin and nervous tissue of a developing embryo. |
| Exogamy | It is the union of the gametes of organisms that are not closely related. It is also used to refer to the union of an individual with another outside the culture or social group to which they belong. |
| exosmosis | It is a type of osmosis where a liquid moves from the interior of a cell to an external medium, through a semipermeable membrane. |
| exostoses | It is a type of benign tumor that extends from the outside of a bone. |
| exonuclease | It is an enzyme that participates in genetic recombination and DNA repair. |
| exon | It is the section of a gene that is kept in the messenger RNA and participates in the coding of the protein of the gene. |
| exotoxin | It is a poisonous substance produced and excreted by some bacteria. They can cause various diseases in humans. Some of the most common are Corynebacterium diphtheriae , which causes diphtheria; Clostridium tetani , which causes tetanus); enterotoxigenic E. coli , which causes severe diarrhea, and golden staphylococcus, which causes toxic shock syndrome. |
Other examples of words with ex – and exo –
Other examples of words that are commonly used in biology, and include the prefixes ex – and exo -, are:
| exospore | It is the outer layer of an algal or fungal spore. |
| exothermic | That produces heat or thermal energy from the inside out. It is generally used to describe a type of chemical reaction that releases heat. |
| exophoria | It is the tendency of one or both eyes to move outward. |
| exogenous | That its origin is external. This term is also used to refer to a flowering plant whose growth occurs by increasing the layers of its outer tissue. |
| exobiology | Science that studies the possibility of life outside the planet Earth. |
| exoplanet | Planet outside the solar system. |
Other related prefixes and suffixes
In addition to the prefixes mentioned, there are other related prefixes and suffixes, including:
- Ecto -: means “outside” or “that is outside.” It appears in words like ectoplasm and ectoderm.
- Endo -: means “inside”, “inside”. For example: endocarp, endoenergetic, endodontics.
- En -: means «in», «within». For example: endemic, encephalon.
- – ectomy : it means “removal” or “separation”. It appears in terms like mastectomy and vasectomy.
Bibliography
- Guzman Lemus, M.; Guzmán Corral, M. Prefixes, suffixes and medical terms. (2009). Spain. Plaza and Valdes.
Leyva, JL Specialized dictionary of technical terms: medical terminology . (2014). Spain. CreateSpace. - Ruíz Torres, F. Dictionary of medical terms. (2000). Spain. CELESA.
