Sound engineering

The twenty-first entry is l’annulation de phase, and the noun at the front of it is the one an English reader is likely to carry into the wrong building. « Annulment » lives in a courtroom: a marriage or a judgment is declared never to have had effect, and the word seldom goes anywhere else. French l’annulation is ordinary. It is what the departure board announces when a train will not run, what a hotel sets out under les conditions d’annulation, and what a match, a concert or an order undergoes when it is called off. The verb is annuler, and le vol est annulé says only that the flight is cancelled. With a pronoun the same verb takes on a third job, and it is the one this list needs. Deux grandeurs s’annulent when they add up to nothing, which is phase cancellation exactly: two identical signals, one of them inverted, summing to silence. Behind all three uses stands the late Latin annullare, to bring to nothing. So the safe default is « cancellation », for the train and for the waves alike, and « annulment » is kept for the rare sentence in which a judge appears.