late 14c., prymrose, from Old French primerose, primerole (12c.) and directly from Medieval Latin prima rosa, literally "first rose," so called because it blooms early in spring (see prime (adj.)). As the name of a pale yellow color, by 1844.
Parallel name primula (c. 1100) is from Old French primerole, from Medieval Latin primula "primrose," shortened from primula veris "firstling of spring," thus properly fem. of Latin primulus, diminutive of primus; but primerole was used in Old French and Middle English of other flowers (cowslips, field daisies). The primrose path is from "Hamlet" I, iii.