birch beer

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun A carbonated soft drink flavored with herb extracts, traditionally of birch tree bark.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun A sweetened, non-alcoholic, sparkling beverage with a wintergreen flavor, traditionally made from the oil of the sweet birch.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun carbonated drink containing an extract from bark of birch trees