Microbiology

The tenth entry is l’unité formant colonie, and the noun that opens it is one an English reader will take for half of itself. Une unité is « a unit »: a unit of measurement, a production unit, a hospital unit, and here the countable thing a laboratory writes on a report. But l’unité is equally « unity », and in that sense it takes no plural and names no object at all — l’unité nationale, l’unité d’un texte, les trois unités of classical drama, where the word means wholeness rather than one of anything. English parted the two long ago and now spends a separate word on each, which is why a translator working the other way has to choose before writing a line. A third use sits between them and belongs behind a counter: vendre à l’unité is to sell singly, by the piece, and le prix à l’unité is what one of them costs. Reading l’unité formant colonie in any sense but the countable one would turn a plate count into a remark about togetherness.