Mahonia \Ma*ho"ni*a\, n. [Named after Bernard McMahon.] (Bot.) The Oregon grape, a species of barberry ({Berberis Aquifolium}), often cultivated for its hollylike foliage. Oregon grape \Or"e*gon grape`\ ([o^]r"[-e]*g[o^]n gr[=a]p`). (Bot.) An evergreen species of barberry ({Berberis Aquifolium}), of Oregon and California; also, its roundish, blue-black berries.