Surveying

Heights in German surveying come from das Nivellement, and the word has kept the shape it had in French. That shape decides its grammar. Nouns borrowed from French in -ment are neuter in German, das Nivellement like das Abonnement, and they form the plural with a bare -s: die Nivellements, with no umlaut and no -e. The ending is still said the French way, nasal and without a final t. Words in -ment that came in from Latin instead sound their t and take -e: das Instrument, die Instrumente. So the ear tells you the plural: if you would not pronounce the t, write an -s. The verb beside it, nivellieren, is fully at home, and it has a second life outside the trade: differences that are nivelliert have been evened out.