lay sth ↔ down phr v [T] 1 to say officially what rules or methods must be obeyed or used 〔正式〕阐述，发布〔规则、方法等〕: strict safety regulations laid down by the government 政府制定的严格的安全条例 2 lay down the law to tell other people what to do in an unpleasant way 〔以令人不快的方式〕发号施令