1. A person, especially an older or married woman, who accompanies a young unmarried woman in public.
2. An older person who attends and supervises a social gathering for young people.
3. A guide or companion whose purpose is to ensure propriety or restrict activity: "to see and feel the rough edges of the society . . . without the filter of official chaperones" (Philip Taubman).

Word History: The chaperon at a high-school dance seems to have little relationship to what was first signified by the English word chaperon, "a hood for a hawk," and not even that much to what the word later meant, "a woman who protects a young single woman." The sense "hood for a hawk," recorded in a Middle English text composed before 1400, reflects the original meaning of the Old French word chaperon, "hood, headgear." In order to understand why our chaperon came to have the sense "protector," we need to know that in French the verb chaperonner, meaning "to cover with a hood," was derived from chaperon and that this verb subsequently developed the figurative sense "to protect." Under the influence of the verb sense the French noun chaperon came to mean "escort," a meaning that was borrowed into English, being found first in a work published in 1720. In its earlier use English chaperon referred to a person, commonly an older woman, who accompanied a young unmarried woman in public to protect her. The English verb chaperon, "to be a chaperon," is first recorded in Jane Austen's Sense and Sensibility, begun in 1796 as a sketch called "Elinor and Marianne" and published as a novel in 1811.