During a discussion with the Chief Rabbi, the Most Rev Justin Welby said it was "excellent" that MPs and peers in the party had accepted the international definition of anti-Semitism "without any riders or caveats of any kind".
The move by the Parliamentary Labour Party was in contrast to the ruling National Executive Committee's decision to adopt the International Holocaust Remembrance Alliance's description with an additional statement saying the move would not prevent criticism of Israel.
Archbishop Justin said the Jewish community had gone through a very demanding few months and hit out at the "unspeakable" trolling of Jews on social media.
Visiting Ephraim Mirvis at his home to mark Rosh Hashanah, the Jewish new year, Mr Welby said: "You've gone through in the last few months a very demanding, stressful time in some ways, over the last few years, I think, with the increase in anti-Jewish attacks across the country, on synagogues, on cemeteries, on individuals and the unspeakable trolling through social media."
The Chief Rabbi said the Jewish community was in a worse position than 12 months ago because at that time it had hope but the position now has "deteriorated".
He added: "What we've found particularly upsetting is that after three years of inaction during which we have waited for the Labour Party to show they are actually serious about tackling anti-Semitism, now we have found during the past summer they haven't even known where the starting blocks are, how do you define it."
Archbishop Justin replied: "Personally, I'm very pleased that the Parliamentary Labour Party has accepted IHRA without any riders or caveats of any kind at all. I think that is excellent news."
Labour MPs and peers voted by 205 to eight on Wednesday to adopt the full IHRA definition and all its examples without any additional statements or caveats into the Parliamentary Labour Party's standing orders.
On Tuesday, the National Executive Committee adopted all of the IHRA's examples but issued a statement alongside that said the party will ensure the changes do "not in any way undermine freedom of expression" on Israel or the rights of Palestinians.
Labour leader Jeremy Corbyn had wanted the NEC to endorse a statement that said it should not be regarded as anti-Semitic to "describe Israel, its policies or the circumstances around its foundation as racist because of their discriminatory impact".
Archbishop Justin said the UK is made up of a collection of "larger or smaller groups, most of which are minorities".
"Therefore, anything that permits attacks on one minority group is a threat to the entire structure of the nation because once you attack one group, why not attack every other group?"
The Archbishop said he wanted the Church of England to adopt the IHRA definition of anti-Semitism formally.
Board of Deputies of British Jews president Marie van der Zyl said: "I would like to express my thanks to the Archbishop of Canterbury for his important intervention in advance of Rosh Hashanah, saying that the Church of England should adopt the IHRA definition of anti-Semitism.
"This moral leadership is warmly welcomed by our community and is a shining example of faith communities uniting against hate."
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