Burden of a Song
.The words repeated in each verse, the chorus or refrain. It is the French bourdon, the big drone of a bagpipe, or double-diapason of an organ, used in fortë parts and choruses.
Burden of Isaiah. The “measure” of a prophecy announcing a calamity, or a denunciation of hardships on those against whom the burden is uttered. (Isa. xiii. 1, etc.)
The burden of proof. The obligation to prove something.