Where does “portal” come from?

I need to analyze this chain carefully, as it appears problematic. The chain given is: English hole | Latin porta | Latin portare | Proto-Indo-European per- | Latin oleum | Ancient Greek ἔλαιον | Latin oleum | Proto-Indo-European -kos This chain doesn't make coherent sense. It jumps between unrelated etymological paths (porta/portare relate to "carry/door," while oleum relates to "oil"). The chain also lists Latin oleum twice and ends with a suffix rather than a root. For the headword "portal" (meaning a door, gate, or entrance), the actual etymology would be: English portal ← Old French portal ← Latin portālis ← Latin porta (door/gate) However, I'm instructed to state only what the chain supports and not invent steps. Given the problematic nature of the provided chain, I

portal (English): An entrance, entry point, or means of entry; A...