ˈkɹɪsməs tɹiː fleɪm tɹiː an ornamented evergreen used as a Christmas decoration medium to tall fir of western North America having a conic crown and branches in tiers; leaves smell of orange when crushed tall timber tree of central and southern Europe having a regular crown and grey bark a terrestrial evergreen shrub or small tree of western Australia having brilliant yellow-orange flowers; parasitic on roots of grasses Australian tree or shrub with red flowers; often used in Christmas decoration