A deciduous tree drops its leaves in the cold season — or, in some hot countries, the dry season — and grows new ones when the weather turns kind again. Oak, maple, and many fruit trees are deciduous. Bare branches in winter are not a sign that the tree has died; it is resting. The opposite kind is evergreen, which keeps its green all year. Biologists also call baby teeth deciduous teeth, because those teeth are meant to fall out. Same idea: something built to come off. It is mainly a school-and-science word. In the park, people just say “the trees that lose their leaves.”