Noun

1. A writ from a court commanding police to perform specified acts
2. A type of security issued by a corporation (usually together with a bond or preferred stock) that gives the holder the right to purchase a certain amount of common stock at a stated price
3. Formal and explicit approval
4. A written assurance that some product or service will be provided or will meet certain specifications

Verb

1. Show to be reasonable or provide adequate ground for
2. Stand behind and guarantee the quality, accuracy, or condition of