To acclimate means to adjust to new conditions or a different environment. When you acclimate to something, your body or mind gradually gets used to changes that felt strange or difficult at first.

If your family moves from Florida to Alaska, you'll need time to acclimate to the cold weather. Your body slowly learns to handle temperatures that would have felt unbearable on your first day. Mountain climbers acclimate to high altitudes by spending days at base camp, letting their bodies adjust to the thinner air before attempting the summit. Without this adjustment period, they could become dangerously sick.

You can also acclimate to new situations beyond physical environments. A student might need a few weeks to acclimate to middle school after elementary school, getting used to changing classes, having different teachers, and managing a locker. The word captures that in-between time when something still feels new but you're actively adapting to it.

The related word acclimation describes the process itself: “The acclimation period for new fish in an aquarium takes about an hour.” Once you've fully acclimated, those once-strange conditions feel normal, and you might forget you ever found them challenging.