Under restraint or control.

(transitive) To formally announce one's arrival at a location or event (usually a hotel) to a proprietor or employee of that location or event in order to secure admission, accommodations, or other services.

An aircraft maintenance check performed approximately every 500-800 flight hours or 200-400 cycles.

A surname.

(transitive) To personally verify that (someone or something) is safe, copacetic, appropriate or satisfactory.

plural of bad check

plural of blank check

(politics) A system for multiple branches of government wherein each has some control over the actions of each of the others.

Third-person singular simple present indicative form of check and balance

Third-person singular simple present indicative form of check out