De or het pyrologie?

The correct Dutch article is:

de pyrologie

Rule Words ending in -logie: always de. See the rule
Meaning (Dutch) (wetenschap) stelselmatige bestudering van vuur

How to use pyrologie

the pyrologiede pyrologie
this pyrologiedeze pyrologie
that pyrologiedie pyrologie
our pyrologieonze pyrologie
your pyrologiejouw pyrologie
every pyrologieelke pyrologie
which pyrologie?welke pyrologie?
a big pyrologie / the big pyrologieeen grote pyrologie, de grote pyrologie

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