It's likely referring to Allium cepa, which is the scientific name for the common onion.
However, "sibuyas dahon" could also refer to:
* Allium fistulosum, which is the scientific name for scallions or spring onions. These are often used in Filipino cuisine like the other type of onion.
* Other Allium species, such as garlic chives or Chinese chives, which are also used in cooking and sometimes called "onion leaves."
To be certain about the specific species, it's best to check the context in which "sibuyas dahon" is used or ask a Filipino speaker.
