Learn Italian: Il nono treno è in ritardo.

Unlike most descriptive adjectives in Italian (like colors or sizes) that usually go after the noun, ordinal numbers like nono (ninth) go right before the noun they describe.

Does nono change its ending depending on the noun?

Yes! Ordinal numbers act like regular adjectives. Because treno is a masculine singular noun, nono takes the masculine singular -o ending. If we were talking about a feminine noun like stazione (station), it would be la nona stazione.

How is nono related to the number nine?

The regular number nine is nove. For the first ten numbers, the ordinal forms are unique words you just have to memorize, rather than following a strict rule. So nove (nine) becomes nono (ninth).

Why does "late" translate to two words, in ritardo?

The Italian word ritardo is actually a noun meaning "delay". So when Italians say a train is late, they literally say it is "in delay" (in ritardo). This is the standard phrase to use when transport or people are running behind schedule.