a figure determined by the intersection of three planes
trihedron in American English
(traiˈhidrən)
nounWord forms: plural-drons or -dra (-drə)
Geometry
the figure determined by three planes meeting in a point
Also: trihedral
Word origin
[1820–30; tri- + -hedron]This word is first recorded in the period 1820–30. Other words that entered Englishat around the same time include: blouse, exogenous, myth, phonetic, takeofftri- is a combining form meaning “three,” used in the formation of compound words. Otherwords that use the affix tri- include: triathlon, trigeminal, triglyph, trinomial, trivial