What are some words that start with the dode prefix is not dodecagon?

You're right, "dodecagon" is the most common word starting with "dode-". However, there are a few others, though they are less common:

* Dodecahedron: A three-dimensional shape with 12 faces.

* Dodecasyllable: A word with 12 syllables.

* Dodecadactyl: A bird with 12 tail feathers.

* Dodecatheon: A genus of flowering plants with 12 stamens.

These words all relate to the number 12, which is the root of the prefix "dode-".