Canada balsam

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

• noun A viscous, yellowish, transparent resin obtained from the balsam fir and used as a cement for glass lenses and for mounting specimens on microscopic slides.

from The Century Dictionary.

• noun etc. See the nouns.

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

• noun A turpentine made from the resin of the balsam fir tree.

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

• noun yellow transparent exudate of the balsam fir; used as a transparent cement in optical devices (especially in microscopy) and as a mounting medium
• noun medium-sized fir of northeastern North America; leaves smell of balsam when crushed; much used for pulpwood and Christmas trees