hairstyle (n.)

Old English hær "hair, a hair," from Proto-Germanic *hēran (source also of Old Saxon, Old Norse, Old High German har, Old Frisian her, Dutch and German haar "hair"), perhaps from PIE *ghers- "to stand out, to bristle, rise to a point" (source also of Lithuanian šerys "bristle;" see horror).

Spelling influenced by Old Norse har and Old English haire "haircloth," from Old French haire, from Frankish *harja or some other Germanic source (see above). Hair-dye is from 1803. To let one's hair down "become familiar" is first recorded 1850. Homeopathic phrase hair of the dog (that bit you), remedy from the same thing that caused the malady, especially a drink on the morning after a debauch, 1540s in English, is in Pliny.

early 14c., stile, "writing instrument, pen, stylus; piece of written discourse, a narrative, treatise;" also "characteristic rhetorical mode of an author, manner or mode of expression," and "way of life, manner, behavior, conduct," from Old French stile, estile "style, fashion, manner; a stake, pale," from Latin stilus "stake, instrument for writing, manner of writing, mode of expression," perhaps from the same source as stick (v.)). Spelling modified incorrectly by influence of Greek stylos "pillar," which probably is not directly related. As distinguished from substance, 1570s. Meaning "mode of dress" is from 1814.