De or het fitting?

The correct Dutch article is:

de fitting

  • Plural: de fittingen / fittings
  • Diminutive: het fittinkje
Rule Words ending in -ing: almost always de. See the rule
Meaning (Dutch) 1. (elektrotechniek) houder van een gloeilamp (bajonetfitting, schroeffitting) 2. verbindingshulpstuk bij buisleidingen, mof, sok

How to use fitting

the fittingde fitting
this fittingdeze fitting
that fittingdie fitting
our fittingonze fitting
your fittingjouw fitting
every fittingelke fitting
which fitting?welke fitting?
a big fitting / the big fittingeen grote fitting, de grote fitting
the fitting (plural)de fittingen, deze fittingen

Dutch words ending in fitting

schroeffitting | lampfitting | bajonetfitting | pijpfitting

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

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