Dictionary.net

• In birds, the main trunk of a bronchus in the lung beyond the ventricle: it gives rise to secondary bronchi.

1920 - A dictionary of scientific terms.
By Henderson, I. F.; Henderson, W. D.

• [Greek] In birds, the main trunk of a bronchus giving rise to secondary bronchi.

1920 - A dictionary of scientific terms (6th edition)
By J.H. Kenneth