It comes from the Greek word "τέσσαρες" (téssares), which means "four".
Here are some examples of words using the prefix "tetra":
* Tetrad: A group of four.
* Tetragon: A four-sided polygon (a quadrilateral).
* Tetrahedron: A three-dimensional shape with four triangular faces.
* Tetrameter: A line of poetry consisting of four metrical feet.
* Tetracycline: A type of antibiotic.