Wiktionary
vb. 1 (context transitive and intransitive English) (&lit boil down English) 2 (context intransitive English) To become reduced (to the most central elements or ingredients: to the essence, core(,) or implication for action). 3 (context transitive English) To reduce (to the most central elements or ingredients: to the essence, core(,) or implication for action).
WordNet
v. be the essential element; "The proposal boils down to a compromise" [syn: reduce, come down]
be cooked until very little liquid is left; "The sauce should reduce to one cup" [syn: reduce, decoct, concentrate]
cook until very little liquid is left; "The cook reduced the sauce by boiling it for a long time" [syn: reduce, concentrate]
Usage examples of "boil down".
I scooped under the snow for teaberry plants to boil down and pour over snowballs for dessert.
Add 3 pints of water, boil down to half the quantity, strain, and add 1 OZ.
Careful watch was kept to make sure the liquid didn't boil down too far.
Dorothy had not spoken Spanish since Owad's arrival and the sisters felt that they were at last making her boil down.
He gave me all sorts of logically conflicting assurances for you, which I think I shall simply boil down to: you have his support.
When there was nothing else to boil down, it always boiled down to hunger.