"material object regarded with awe as having mysterious powers or being the representative of a deity that may be worshipped through it," 1610s, fatisso, from Portuguese feitiço "charm, sorcery, allurement," noun use of an adjective meaning "artificial."
The Portuguese adjective is from Latin facticius "made by art, artificial," from facere "to make, do, produce" (from PIE root *dhe- "to set, put;" compare French factice "artificial," restored from Old French faitise, from Latin facticius). Via the French word, Middle English had fetis, fetice (adj.) "cleverly made, neat, elegant" (of things), "handsome, pretty, neat" (of persons). But in the Middle Ages the Romanic derivatives of the word took on magical senses; compare Portuguese feiticeria "sorcery, witchcraft," feiticeiro "sorcerer, wizard." Latin facticius in Spanish has become hechizo "artificial, imitated," also "bewitchment, fascination."
The specific Portuguese use of the word that brought it to English probably began among Portuguese sailors and traders who used the word as a name for charms and talismans worshipped by the inhabitants of the Guinea coast of Africa. It was picked up and popularized in anthropology by Charles de Brosses' "Du culte des dieux fétiches" (1760), which influenced the word's spelling in English (French fétiche also is borrowed 18c. from the Portuguese word).
Any material image of a religious idea is an idol; a material object in which force is supposed to be concentrated is a Fetish; a material object, or a class of material objects, plants, or animals, which is regarded by man with superstitious respect, and between whom and man there is supposed to exist an invisible but effective force, is a Totem. [J. Fitzgerald Lee, "The Greater Exodus," London, 1903]
Figurative sense of "something irrationally revered, object of blind devotion" appears to be an extension made by the New England Transcendentalists (1837). For sexual sense (1897), see fetishism.