Is ethical non-monogamy the same as polyamory?

The confusion is understandable, because the two terms appear together constantly. ENM is the category; polyamory is one of the things in it. Ethical non-monogamy covers swinging, open relationships, relationship anarchy, polyamory and arrangements that have no name at all. The word ethical is doing real work: it signals that everyone involved knows and agrees, which is what separates all of these from cheating.

Polyamory is specific about what it includes: multiple romantic relationships, usually ongoing, with the knowledge and consent of everyone involved. A polyamorous person may have two partners they love, a primary partner and a second relationship, or several relationships arranged without hierarchy. The answer on what polyamory is covers the structure itself, and the one on the types of polyamory covers the vocabulary people use for the different shapes.

Open relationship usually means something narrower: one committed couple whose agreement allows connections outside it, typically sexual and often occasional, without either partner building a second romantic relationship. That is ENM, but it is generally not described as polyamory. Swinging is narrower still — recreational, couple-anchored, often social and event-based — and is also ENM. The answer comparing swinging and polyamory works through the two forms that get confused most often.

The practical reason to care about the difference is that these words are how people describe what they are offering. A profile that says ENM is saying that everyone consents, but not what the arrangement is; a profile that says polyamorous is saying that romance, not only sex, is on the table. In conversation the label is a starting point and the details are the substance: what each person wants, how much time is available, what is shared with whom, and what safer-sex terms apply. The answers on ENM dating and on what ENM means cover those practical questions.