To remain alive through the winter: sheep that overwintered on the steppe.
To pass or spend the winter: We usually overwinter in the Bahamas.
Occurring during the period of winter.
American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.