Olive trees refer to a species of small tree that belongs to the genus Olea and is native to the Mediterranean region. These trees are known for their longevity, with some olive trees being thousands of years old. They produce fruit in the form of olives which have various uses including consumption as food or for making oil. The phrase "olive trees" can also be used metaphorically to refer to something that is steady and unchanging, like a rock or an anchor.