My guess is ‘vegetala oleo’ (or, ‘vegetoleo’ for short).
Wikipedia suggests legoma oleo. I find this term strange though, because vegetable oil can also be oil from plant-like things that are not vegetables (like nuts or seeds). The English term is also used for this oddly enough.¹ Several other languages use a word relating to plants or vegetation in general rather than vegetables specifically. Considering all sources of the page are in English, I presume an English speaker chose the term.
1) From the Oxford dictionary:
an oil derived from plants, e.g., canola oil, olive oil, sunflower oil.