coniferous evergreen shrub of northern regions, late 14c., gynypre, etc. (later altered to conform to Latin), from Latin iuniperus "the juniper tree" (source of Old French genevre, French genièvre, Spanish enebro, Portuguese zimbro, Italian ginepro, and, via Old French, Middle Dutch genever), a word of uncertain origin.
Perhaps it is related to iunco "reed," but there are phonetic difficulties. Watkins has it from PIE *yoini-paros "bearing juniper berries," from *yoi-ni- "juniper berry," perhaps from a non-IE language, + *-paro "producing" (from PIE root *pere-(1) "to produce, procure"). Applied to various North American species from 1748. In the English Bible (late 14c.), it renders Hebrew rethem, the name of a white-flowered shrub unrelated to the European evergreen, as the Latin word does in the Vulgate.