boil down

(verb) be the essential element. Synonyms: reduce, come down, boil down. Example: "The proposal boils down to a compromise."

(verb) be cooked until very little liquid is left. Synonyms: boil down, reduce, decoct, concentrate. Example: "The sauce should reduce to one cup."

(verb) cook until very little liquid is left. Synonyms: reduce, boil down, concentrate. Example: "The cook reduced the sauce by boiling it for a long time."