gray birch

Từ điển WordNet v3.1 - WordNet Dictionary

noun

medium-sized birch of eastern North America having white or pale grey bark and valueless wood;
occurs often as a second-growth forest tree
• Syn:
grey birch, American grey birch, American gray birch, Betula populifolia
• Hypernyms:
birch, birch tree
• Member Holonyms:
Betula, genus Betula