from The American Heritage® Dictionary of the English Language, 4th Edition
- n. The elevation in a mountainous region above which trees do not grow.
- n. The northern or southern latitude beyond which trees do not grow.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. the height or limit beyond which trees do not grow in mountainous or arctic regions.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- n. line marking the upper limit of tree growth in mountains or northern latitudes
Sorry, no etymologies found.