ennea-

Ennea- is a combining form used like a prefix meaning “nine.” It is used in some scientific and other technical terms.

Ennea- comes from the Greek ennéa, meaning “nine.” The Latin counterpart is nōnus, meaning “ninth” and source of the combining form nona-, which you can learn more about in our Words That Use articles for that form.

An enneagon is “a polygon having nine angles and nine sides.” It’s also known as a nonagon.

The first part of the word, ennea-, means “nine.” The -gon portion of the word may also look familiar: it is a combining form meaning “angled” or “angular,” from the Greek gōnía. Enneagon literally translates to “nine-angled.”

Enneagon comes from the Greek enneágōnos, which features the equivalent form of ennea- in the language.

Another word you may have encountered that features ennea- is the Enneagram, a popular psychological model that categorizes human personality into nine types.

What are some words that use or are related to the combining form ennea-?

• ennead
• enneahedron
• enneastyle
• enneastylos
• enneasyllabic (using the equivalent form of ennea- in Greek)

What are some other forms that ennea- may be commonly confused with?

• -enne
• endo-

The combining form -hedron means “face,” in the sense of a face of a geometrical solid figure, i.e., a cube has six faces. How many faces does an enneahedron have?