dihedral angle vs torsion angle

dihedral angle and torsion angle both are nouns.

Word	Noun	Adjective	Verb	Adverb
dihedral angle	Yes	No	No	No
torsion angle	Yes	No	No	No

As nouns, dihedral angle and torsion angle are synonyms defined as:

dihedral angle (noun)	torsion angle (noun)
the angle between two planes.	the angle between two planes.