numeral
fourteen
A1
'vierzehn' is the cardinal number meaning 'fourteen'. It’s an invariable numeral used for counting and quantifying (vierzehn Jahre). As a numeral it doesn't decline; when used attributively before nouns German usually leaves it unchanged. It can function as a noun (das Vierzehnte) when ordinalized or nominalized.
Examples
Die Schule betreute vierzehn Schüler, die wegen des Ausflugs eine Einwilligung brauchten.
The school supervised fourteen pupils who needed consent because of the trip.
Ich bin vierzehn Jahre alt.
I'm fourteen years old.
Details
Mnemonics
Imagine the digits 1 and 4 side by side to remember 14
vierzehn — starts with 'vier' (four) so think 'four-teen'
Notes
Cardinal number. Use 'vierzehn' in dates, ages, counts.