trier

Anglo-Norman trier (to sort, to try, to test) probably comes from a Vulgar Latin *trītāre, possibly related to Latin terere (to rub, to grind, to wear down) or to trēs (three — from the idea of a three-part sorting process). The word entered English in the thirteenth century as 'trial,' naming both the act of testing and the legal proceeding. A trial is a test — an attempt to determine the truth by subjecting claims to examination.

The medieval trial was not always rational. Trial by ordeal — holding a hot iron, plunging a hand into boiling water, being thrown into a river to see if you floated — was the dominant form of divine judgment in early medieval Europe. The Fourth Lateran Council in 1215 prohibited clergy from participating in ordeals, effectively ending the practice. Trial by jury replaced it, gradually. The word 'trial' survived the shift from divine judgment to human judgment without changing.

The adversarial trial — prosecution versus defense, each presenting evidence to a neutral jury — is an Anglo-American invention. Continental European systems use the inquisitorial method, where the judge actively investigates. The adversarial system treats a trial as a contest. The inquisitorial system treats it as an inquiry. Both are called 'trials' in English, but the word maps more naturally onto the adversarial model — a trial is a test, and a test implies a competition.

The word's non-legal meanings preserve the testing sense. A trial run, a trial period, trial and error, trials and tribulations. A trial is anything that tests you — an experience that sorts what you are made of from what you are not. The legal trial and the metaphorical trial are the same word because they do the same thing: subject someone or something to examination and see what remains.