What defines ethnicity?

[Atlantic Reptilian]

Mentality.

[Thracian]

Genetic ancestry.

[vader]

A combination of culture, language, and genetic heritage. I am dual national with portugal and am genetically Portuguese and am well aware of the culture while learning the language. So id say I fit the criteria fine.

[Creoda]

Blood + culture/identity, what else? The level of cultural belonging is negotiable on a case by case basis, but the level of ancestral belonging is non-negotiable. Otherwise an ethnicity is meaningless, and anyone can be anything.

Religion is actually very important for many ethnic identities. Or at least religious tradition.

For example the Irish do not identify as British because they are Catholic, not Protestant.

Historically perhaps, but the main reason the Irish don't identify as British now is because of secular Irish Republicanism and the consequent fact that it's an independent country. Neither nationality is necessarily tied to a religious belonging, just associated with.

[Sarin]

In Indian context , it can said to be determined by the mother language (or alternatively , the region that has been habitat of its speakers since time immemorial) thereby cutting across the lines of religion/caste/local genetics etc. . So yes , language/corresponding region eg. Punjabi , Tamil , Bengali etc. .

[Todesritter]

Genetics, cultural background, languages (including which languages and cultures you choose to use and live among later), as well as mindset and mentality are all factors that contribute towards ethnicity. Religions matter only to a certain extent, if they are at least somewhat native to the ethnicity you're identifying with or not (even if white-passing visually, I don't consider west European muslims to be truly west European, but being Protestant in a Catholic majority area eg. Bavaria doesn't necessarily preclude you from being part of that ethnicity unless it reaches deeply into your cultural background. and nowadays individual adult choice of religion does not mean much in terms of ethnicity and cultural belongings, people convert because they agree or disagree with the doctrine).

Mentality has to some extent be tied to genetics and is an often forgotten part of ethnicity, and mentality relates to why certain religions are by default alien or un-european.

[Peterski]

Genetic ancestry.

What if your biological parents were Russian but you got adopted as a toddler by a French couple.

You are not growing up as a French then?

[Aldaris]

Common ancestry and to a lesser degree a common culture. There are of course some other extended or narrowed definitions, but they make little sense. For example. you probably wouldn't consider the actual ethnic Arabs from Saudi Arabia, UAE or Oman who share both the ancestry and culture to be of the same ethnicity as for example Persians just because they share a great deal of culture with them, including religion. Even if they actually started to spoke Arabic back then, the essential common ancestry requirement would still not be there. I think the best you can do is make clear examples like that, but you won't get a one hundred percent accurate definition.

[Jana]

Interesting, looks like he is prob a german culturally speaking but a Baltic genetically speaking, a Germanized Balt

Is thats results comum in Prussia? i thought that there a mass german imigration to Prussia

His results are typical for particular sub-region of East Prussia where he is from.

[Foghorn]

Language, everything else is a fairy tale.