De or het rader?

The correct Dutch article is:

de rader

Meaning (Dutch) (verouderd) raadgever, raadsman

How to use rader

the raderde rader
this raderdeze rader
that raderdie rader
our raderonze rader
your raderjouw rader
every raderelke rader
which rader?welke rader?
a big rader / the big radereen grote rader, de grote rader

Dutch words ending in rader

waterader | zilverader | afrader | grader | aanrader | verrader | landverrader | volksverrader | aartsverrader | trader | daytrader

In compound words, the last part decides the article. See the rule

Dutch words starting with rader

raderboot | raderstoomboot | raderwerk | raderwiel | raderkast | raderuurwerk | raderwieltje

Meaning, plural, diminutive, pronunciation and translations: WikiWoordenboek (Dutch Wiktionary) (CC BY-SA 4.0). Example sentences: Tatoeba (CC BY 2.0 FR).