[v] exert a force or cause a strain upon; "This tax bears down on the lower middle class"
[v] pay special attention to; "The lectures bore down on the political background"
[v] exert full strength, as in baseball; "The pitcher bore down"
[v] to make a rush at or sudden attack upon, as in battle; "he saw Jess charging at him with a pitchfork."
[v] contract the abdominal muscles during childbirth to ease delivery
[v] exert a force with a heavy weight; "The snow bore down on the roof"