De or het ovenkamer?

The correct Dutch article is:

de ovenkamer

How to use ovenkamer

the ovenkamerde ovenkamer
this ovenkamerdeze ovenkamer
that ovenkamerdie ovenkamer
our ovenkameronze ovenkamer
your ovenkamerjouw ovenkamer
every ovenkamerelke ovenkamer
which ovenkamer?welke ovenkamer?
a big ovenkamer / the big ovenkamereen grote ovenkamer, de grote ovenkamer

Dutch words ending in ovenkamer

bovenkamer

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