To acclimatize means to gradually adjust to a new environment or different conditions. When you acclimatize, your body and mind slowly get used to changes in temperature, altitude, schedule, or surroundings.

Mountain climbers acclimatize to high altitudes by spending time at base camps before attempting the summit. At high elevations, there's less oxygen in the air, and rushing to the top too quickly can make people seriously ill. By acclimatizing over several days or weeks, their bodies learn to function with less oxygen.

You might acclimatize to a new school by learning where classrooms are, figuring out lunch routines, and getting comfortable with new teachers. Plants acclimatize when gardeners gradually expose them to outdoor conditions before transplanting them from a greenhouse. Even moving to a different climate requires acclimatizing: someone relocating from Alaska to Arizona needs time to adjust to the intense heat.

The key idea is gradual change. Acclimatizing isn't instant. Your body or mind needs repeated exposure to new conditions to adapt successfully. Think of it like learning to swim in cold water: you don't just dive in. You wade in slowly, letting yourself adjust bit by bit until the temperature feels normal.