Oak is a nature name taken straight from the tree, whose name goes back to the Old English ac and simply means "oak tree". Oaks have stood for strength and endurance in many cultures, from the sacred groves of the Celts to the state trees of several US states. As a first name Oak has grown with the trend toward short nature names: from number 4149 in 2015 to number 2142 in 2023, its best rank, and number 2344 in 2025.