Spaceflight

One entry on this list is das Wohnmodul, the part of a station where the crew sleeps and eats, and the article in front of it is not decoration. German has two nouns spelt Modul and tells them apart by gender alone. Das Modul, neuter, is a self-contained unit that can be added or swapped: a station module, a software module, a unit of a university course. Der Modul, masculine, is a number — the modulus of mathematics and of materials science, as in der Elastizitätsmodul, which says how stiff a material is. Both go back to Latin modulus, a small measure. So an engineer who writes der Modul about a station has not made a slip of spelling but named a quantity, and a careful reader stops. A compound takes its gender from its last part, which is why every module of a station, from das Wohnmodul to das Labormodul, is neuter.