Coolibah is an Australian word that refers to:
* A type of eucalyptus tree: Specifically, *Eucalyptus coolibah*, known for its hard, durable wood and its ability to thrive in arid conditions.
* The wood from this tree: Coolibah wood is highly valued for its strength and durability, making it suitable for a variety of applications.
It's possible that the misspelling "coombiyah" is simply a phonetic approximation of the word "Coolibah".
If you have a specific context in mind, it might be helpful to provide more information so I can give you a more accurate answer.