tetraeder

From the prefix tetra-, appended by Ancient Greek ἕδρα (hédra, “seat”).

tetraeder n (singular definite tetraederet, plural indefinite tetraedre)

1. (geometry) tetrahedron

• “tetraeder” in Den Danske Ordbog

From tetra- +‎ -eder.

tetraeder n (definite singular tetraederet or tetraedret, indefinite plural tetraeder or tetraedre, definite plural tetraedra or tetraedrene)

1. (geometry) a tetrahedron

• tetraedrisk

• “tetraeder” in The Bokmål Dictionary.
• “tetraeder” in Det Norske Akademis ordbok (NAOB).

From tetra- +‎ -eder.

tetraeder n (definite singular tetraederet, indefinite plural tetraeder, definite plural tetraedera)

1. (geometry) a tetrahedron

• tetraedrisk

• “tetraeder” in The Nynorsk Dictionary.

tetraeder c

1. (geometry) a tetrahedron