Yiddishkeit (Yiddish: ייִדישקייט — yidishkeyt using the YIVO transliteration rules, yidishkayt in quasi-phonetic transcription) literally means "Jewishness", i. e. "a Jewish way of life", in the Yiddish language. It can refer to Judaism or forms of Orthodox Judaism when used by religious or Orthodox Jews. In a more general sense it has come to mean the "Jewishness" or "Jewish essence" of Ashkenazi Jews in general and the traditional Yiddish-speaking Jews of Eastern and Central Europe in particular.
From a more secular perspective it is associated with the popular culture or folk practices of Yiddish-speaking Jews, such as popular religious traditions, Eastern European Jewish cuisine, Yiddish humour, shtetl life, and klezmer music, among other things.
Before the Haskalah and the Jewish emancipation in Europe, central to Yiddishkeit were Torah study and Talmudical studies for men, and a family and communal life governed by the observance of Jewish Law for men and women. Among Haredi Jews of Eastern European descent, who compose the majority of Jews who still speak Yiddish in their everyday lives, the word has retained this meaning.
But with secularization, Yiddishkeit has come to encompass not just traditional Jewish religious practice, but a broad range of movements, ideologies, practices, and traditions in which Ashkenazi Jews have participated and retained their sense of "Jewishness". Yiddishkeit has been identified in manners of speech, in styles of humor, in patterns of association, in culture and education. Another quality often associated with Yiddishkeit is an emotional attachment and identification with the Jewish people. In these latter exceptions of the term, the most common Latinate spelling is yiddishkayt.
- Competing ways of transcription exist for the suffix: -keit, based on the orthography of Standard Modern German; -keyt using the YIVO transliteration, and -kayt, a quasi-phonetic transcription used by a majority of linguists and philologists, particularly in the U.S., and favored by Uriel Weinreich in his College Yiddish.