either of two high-altitude pine tree (Pinus aristata and P. longaeva) of the W U.S., having needles in clusters of five and cones with bristles: they are known for their often twisted, gnarled appearance and extremely long life
See bristlecone pine in American Heritage Dictionary 4
noun
Either of two small slow-growing pines (Pinus aristata or P. longaeva) found at higher elevations of the western United States, having needles in fascicles of five. Specimens of P. longaeva in the Sierra Nevada are the oldest known living trees, achieving ages well over 4,000 years.