De or het ot-en-sienkleding?

The correct Dutch article is:

de ot-en-sienkleding

Rule Words ending in -ing: almost always de. See the rule
Meaning (Dutch) (kleding) nostalgische, ouderwetse kinderkleding die doet denken aan het begin van de 20e eeuw.

How to use ot-en-sienkleding

the ot-en-sienkledingde ot-en-sienkleding
this ot-en-sienkledingdeze ot-en-sienkleding
that ot-en-sienkledingdie ot-en-sienkleding
our ot-en-sienkledingonze ot-en-sienkleding
your ot-en-sienkledingjouw ot-en-sienkleding
every ot-en-sienkledingelke ot-en-sienkleding
which ot-en-sienkleding?welke ot-en-sienkleding?
a big ot-en-sienkleding / the big ot-en-sienkledingeen grote ot-en-sienkleding, de grote ot-en-sienkleding

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