Short answer: theoretically yes, but there are exceptions…
A slightly longer one: Not at all, but statistically most often they are used in the same way to mean the same thing.
Now for a more full answer… a guy in a YouTube comment asked me "If Zionism isn't Judaism, why is Congress passing laws saying it is, laws now passed and, on the books, saying that anti-Zionism is anti Semitism? Looks like Jews want them to be one and the same." – And here's my reply:
I am not an American, so I can't explain why Americans do things.
I am not a politician, I don't understand those most of the time either. They don't decide facts, they sometimes manage to rewrite historical narratives, it doesn't always work, not on everyone at least.
So some basic facts:
Judaism is a religion. You don't have to be born into it, you can convert. That's how the mid-eastern ancient Bney Yisrael are no longer the only genetic source of ethnic Jews. You have African, Central Asian and even Mongol and Japanese Jews.
The Jewish people is also a culture. A very diverse and heterogeneous culture, because for hundreds of years of living as a diaspora all over the world, customs, languages and traditions changed, but a lot of the basics remained, such as common faith principles, holy days observed and so on. One of the pillars is a longing for the return to the land of Israel and Jerusalem. That hope is woven into texts, it's part of the Passover blessings and the wedding ceremony. Zion is one of the many names of Jerusalem, and also sometimes used to refer to the entire land of Israel. "It depends on the context" as professor Gay put it do well.
Zionism is the latest attempt (and so far the first successful one) to return to the holy land that had very few Jews remaining between year 70CE to about 1850, based on the European momentum of the formation of nation states, and seeing that the Jewish people deserve a state as well – whether as a place to recreate their national home or to escape persecution. Lots of non-Jews think that Jews should have their own country. It was voted in the UN on November 29, 1947 and a majority of countries were in favour, that can be counted as Zionist thinking or a support of Zionism. Joe Biden sees himself as a Zionist, and he's obviously not Jewish.
Anti Zionism: people who believe Jews should not have their own state or that the state of Israel has lost all (or never had any) justified reason to be founded. There are Antisemites who don't want Jews in their lives, and prefer they all piss off to their own country, and in a twisted way that's also a kind of Zionism. Others hate us so much that they would not want Jews to have a state either, those would be anti-Zionists.
There are also a few Jews that are not in favour of a Jewish state. Famous secular examples are Jon Stuart, Gabor Mate, Noam Chomsky, Sam Seder among many others who identify as anti-zionists. On the very religious end you have messianic Neturey Karta, a Jewish sect that believe that Jews should only return to Israel when the messiah comes back (Somewhat like a second coming of Jesus but the Jewish version).
Final definition: Modern religious "zionism" (See also previous post in this blog). I don't even give it the respect of capitalizing the Z because I don't think it has anything to do with why my grandparents left their families in Europe to build this country. They believe that Jews deserve an "ethnically pure" Israel, and it should be from the river to the sea and beyond (some aspiring to include most of modern Jordan, Lebanon and Syria), and that it should be ethnically clean of non-Jews. I find that idea unhinged, immoral and criminal, yet they are vocal enough (and targeted enough by the Palestinians in the media) that people started thinking that is the "true" Zionism. I assure you it definitely was not the secular Zionism of the 19th and most of the 20th century that I was brought up on. They are the ones building towns on lands that were supposed to be occupied only temporarily, against all international rules of occupation. They are probably also to blame for lobbying for all those nutty rules in America. That's why the pro-Palestinian call "From the river to the sea" is the racist genocidal call of the other side. The right wing extremists that can't see two states next to each other call "From the river to the sea" meaning either Arabs or Jews but not a mix or a two state solution. Whether used as an anti-Arab or an Antisemitic call, it's racist and genocidal, and not the direction any self-respecting humanist or leftist/liberal/progressive should be taking. The liberal, Progressive, humanistic solution is two states – Not an intifada or any sort of genocide. Maybe in a generation we can consider becoming a confederation so people could live anywhere and move around more freely, but not before hatred cools down and the education systems stop poisoning the young minds on both sides.
Summing up: Zionism is not only Jewish, a very small number of Jews are anti-Zionists, but the majority of anti Zionists believe Israel should be destroyed so they seem to be fine with dead Jews, so therefore Antisemitic. I hope that covers it.
