moun·tain·eer·ing (moun?tn-?r??ng)n. The climbing of mountains, especially using special equipment and techniques on rock, ice, or snow. Also called mountain climbing.American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.