A valve in a pipeline which allows the liquid or gas to flow in one direction only.

Alternative form of bed check

(chiefly US) In a dormitory, as in the military or at a childrens' campground or in a boarding school, an inspection after bedtime by authorities to ensure that everyone is present and in his or her bed.

(idiomatic) To permit someone to continue onward, e.g. through a security checkpoint, after verifying their identity, tickets, etc.

Misspelling of rain check.

plural of check valve

present participle of check and balance

(idiomatic) Provide mutual oversight and limitation by independent organizations in order to prevent abuses of power.

(idiomatic) The mutual oversight provided by a system of independent organizations with control over each other.

Alternative form of gut check