"religious system revealed by Muhammad," 1816, from Arabic islam, literally "submission" (to the will of God), from root of aslama "he resigned, he surrendered, he submitted," causative conjunction of salima "he was safe," and related to salam "peace."
... Islam is the only major religion, along with Buddhism (if we consider the name of the religion to come from Budd, the Divine Intellect, and not the Buddha), whose name is not related to a person or ethnic group, but to the central idea of the religion. ["The Heart of Islam: Enduring Values for Humanity," Seyyed Hossein Nasr, 2002]
Earlier English names for the faith include Mahometry (late 15c.), Muhammadism (1610s), Islamism (1747), and Ismaelism (c. 1600; see Ismailite). The Ismailites were not numerous in Islam, but among them were the powerful Fatimid dynasty in Egypt and the Assassins, both of which loomed large in European imagination. This use also is in part from Ishmaelite, a name formerly given (especially by Jews) to Arabs, as descendants of Ishmael (q.v.).
"one who professes Islam," 1610s, from Arabic muslim "one who submits" (to the faith), from root of aslama "he resigned." Related to Islam. From 1777 as an adjective.
Arabic or Muslim greeting, 1610s, from Arabic salam (also in Urdu, Persian), literally "peace" (compare Hebrew shalom); in full, (as)salam 'alaikum "peace be upon you," from base of salima "he was safe" (compare Islam, Muslim). Formerly used generically of ceremonious salutations in India and elsewhere in Asia. As a verb, "to salute with a 'salaam,'" by 1690s.
"hostility or discrimination against Muslims," supposedly rooted in dread or hatred of Islam, by 1996, from Islam + -phobia, as used in Judaeophobia, Francophobia, etc. Related: Islamophobic; Islamophobe.
The term [a report by the liberal think-tank Runnymede Trust] uses, 'Islamophobia,' is so recently coined that it has yet to be recognised in the Oxford English Dictionary, but according to the trust the phenomenon it refers to 'has existed in western countries and cultures for centuries.' ["Islamophobia," Third Way, April 1997]
The related words have been in occasional use for more than a century, however. Islamophobe is attested in 1877 in English and by 1914 in French.