The spelling of the word "Trior" may seem confusing, but it can be explained using the International Phonetic Alphabet (IPA). In IPA, "Trior" would be written as /traɪər/. The "tr" represents a consonant cluster, with the "t" and "r" sounds pronounced together. The "ai" represents a diphthong, where the sounds "a" (æ) and "i" (ɪ) are blended together. Finally, the "or" represents another consonant cluster, with the "o" (ɔ) and "r" sounds pronounced together. With this understanding, the spelling of "Trior" becomes clearer.
A person appointed to ascertain whether a challenge to a panel of jurors, or to a single juror, is just.
Etymological and pronouncing dictionary of the English language. By Stormonth, James, Phelp, P. H. Published 1874.