Antisemitism may be manifested in many ways, ranging from expressions of hatred of or discrimination against individual Jews to organized pogroms by mobs, state police, or even military attacks on entire Jewish communities. Although the term did not come into common usage until the 19th century, it is now also applied to historic anti-Jewish incidents. Notable instances of persecution include the Rhineland massacres preceding the First Crusade in 1096, the Edict of Expulsion from England in 1290, the massacres of Spanish Jews in 1391, the persecutions of the Spanish Inquisition, the expulsion from Spain in 1492, the Cossack massacres in Ukraine from 1648 to 1657, various anti-Jewish pogroms in the Russian Empire between 1821 and 1906, the 1894–1906 Dreyfus affair in France, the Holocaust in German-occupied Europe during World War II, official Soviet anti-Jewish policies, and Arab and Muslim involvement in the Jewish exodus from Arab and Muslim countries.
The root word Semite gives the false impression that antisemitism is directed against all Semitic people, e.g., including Arabs and Assyrians. The compound word antisemite was popularized in Germany in 1879 as a scientific-sounding term for Judenhass ("Jew-hatred"), and has been its common use since then.
The origin of "antisemitic" terminologies is found in the responses of Moritz Steinschneider to the views of Ernest Renan. As Alex Bein writes: "The compound anti-Semitism appears to have been used first by Steinschneider, who challenged Renan on account of his 'anti-Semitic prejudices' ." Avner Falk similarly writes: 'The German word antisemitisch was first used in 1860 by the Austrian Jewish scholar Moritz Steinschneider (1816–1907) in the phrase antisemitische Vorurteile (antisemitic prejudices). Steinschneider used this phrase to characterise the French philosopher Ernest Renan's false ideas about how "Semitic races" were inferior to "Aryan races"'.
Pseudoscientific theories concerning race, civilization, and "progress" had become quite widespread in Europe in the second half of the 19th century, especially as Prussian nationalistic historian Heinrich von Treitschke did much to promote this form of racism. He coined the phrase "the Jews are our misfortune" which would later be widely used by Nazis. According to Avner Falk, Treitschke uses the term "Semitic" almost synonymously with "Jewish", in contrast to Renan's use of it to refer to a whole range of peoples, based generally on linguistic criteria.