Any of the two points that divide an ordered distribution into three parts, each containing a third of the population.(noun)
Any one of the three groups so divided.(noun)
Wiktionary.org : Text is available under the Creative Commons Attribution-ShareAlike License
Use "tertile" in a sentence
"About 55% of those whose brains were in the upper tertile (third) of atrophy developed Alzheimer's, while none of those whose brains in the bottom tertile (little or no atrophy) developed Alzheimer's."
"Risk for developing metabolic syndrome was highest in the tertile with the greatest weight fluctuations, independent of whether these subjects gained weight overall or not."
"For the Beer brand, the overall TV ROI was $0.23 and among the high HSP index tertile of programs it was $1.61."