Number & MeasureGreek → English
Trichotomy
/traɪˈkɑtəmi/noun
A division into three parts, and in mathematics the law that any two real numbers stand in exactly one of the relations less than, equal to, or greater than.
The Greek roots
τριχῇ
trichêi
in three parts
τέμνειν
témnein
to cut
Literally: “a cutting in three”
The story of the word
This one was built in English in the seventeenth century on the pattern of dichotomy, which is why it looks older than it is. The trich- has nothing to do with hair: θρίξ, hair, gives trichology and trichinosis, while this word takes τριχῇ, meaning threefold. Theologians used it first for the division of a person into body, soul and spirit; mathematicians took it over for an ordering axiom.
- How it travelled
- Ancient Greek → scientific coinage → English
- First recorded
- 17th century
Same family
dichotomyanatomyatomtome
In a sentence
Trichotomy fails for complex numbers, which is why you cannot order them.
He proposed a trichotomy where everyone else saw two camps.