"act as a chaperon, attend (an unmarried girl or woman) in public," 1792, also chaperone, from chaperon (n.), or from French chaperonner, from the noun in French. Related: Chaperoned; chaperoning.
"woman accompanying and guiding a younger, unmarried lady in public," 1720, from French chaperon "protector," especially "female companion to a young woman," earlier "head covering, hood" (c. 1400), from Old French chaperon "hood, cowl" (12c.), diminutive of chape "cape" (see cap (n.)). "... English writers often erroneously spell it chaperone, app. under the supposition that it requires a fem. termination" [OED]. The notion is of "covering" the socially vulnerable one. The word had been used in Middle English in the literal sense "hooded cloak."
"May I ask what is a chaperon?"
"A married lady; without whom no unmarried one can be seen in public. If the damsel be five and forty, she cannot appear without the matron; and if the matron be fifteen, it will do."
[Catharine Hutton, "The Welsh Mountaineer," London, 1817]
1570s, "cloth spread over a saddle," also "personal dress and ornaments," from French caparasson (15c., Modern French caparaçon), from Spanish caparazón, perhaps from augmentative of Old Provençal caparasso "a mantle with a hood," or Medieval Latin caparo, the name of a type of cape worn by women, literally "chaperon" (see chaperon (n.)). Past participle adjective caparisoned is attested from c. 1600, from a verb caparison (1590s), from French caparaçonner, from caparaçon.
1660s, "chief lady in waiting upon the queen of Spain," also "an elderly woman in charge of girls from a Spanish family," from Spanish dueña "married lady, mistress" (fem. of dueño "master"), from Latin domina "lady, mistress of the house," from Latin domus "house" (from PIE root *dem- "house, household"). Sense extended in English to "any elderly woman chaperon of a younger woman" (1708).
"covering," Old English hod "a hood, soft covering for the head" (usually extending over the back of the neck and often attached to a garment worn about the body), from Proto-Germanic *hōd- (source also of Old Saxon, Old Frisian hod "hood," Middle Dutch hoet, Dutch hoed "hat," Old High German huot "helmet, hat," German Hut "hat," Old Frisian hode "guard, protection"), which is of uncertain etymology, perhaps from PIE *kadh- "to cover" (see hat).
Modern spelling is early 1400s to indicate a "long" vowel, which is no longer pronounced as such. Used for hood-like things or animal parts from 17c. Meaning "Foldable or removable cover for a carriage to protect the occupants" is from 1826; meaning "sunshade of a baby-carriage" is by 1866. Meaning "hinged cover for an automobile engine" attested by 1905 (in U.K. generally called a bonnet). Little Red Riding Hood (1729) translates Charles Perrault's Petit Chaperon Rouge ("Contes du Temps Passé" 1697).
As slang for a fool, 1719, perhaps an extended form of goose (n.) in this sense, or a play on gooseberry fool in the cookery sense. Gooseberry also meant "a chaperon" (1837) and "a marvelous tale." Old Gooseberry for "the Devil" is recorded from 1796. In euphemistic explanations of reproduction to children, babies sometimes were said to be found under a gooseberry bush.