Rule for neuter · das
-um → das · 1.1% (but Raum, Baum, Traum are der!)
Borrowed nouns ending in -um (mostly of Latin origin) are usually neuter: we say das Publikum, das Zentrum, or das Wachstum. This pattern only covers 1.1% of our 2,400-word list, so it's not one of the biggest rules, but it's worth knowing for these learned or technical words. Watch out though: not every noun ending in -um is neuter - der Raum, der Baum, der Traum, and der Konsum are classic exceptions, along with der Zeitraum, der Wohnraum, der Spielraum, and der Innenraum. As a rule of thumb: scholarly loanwords (technical or abstract terms, often plural in -en/-a) reliably take das, while older core German words need to be checked individually.