hollow oak
an oak tree with a diameter of at least 63 cm or a circumference of at least two meters at breast height, protected under the Norwegian Natural Diversity Act
en-GB/ˈhɒləʊ ˈəʊk/
en-US/ˈhɑloʊ ˈoʊk/
an oak tree with a diameter of at least 63 cm or a circumference of at least two meters at breast height, protected under the Norwegian Natural Diversity Act