Charter

1.  Broadly, the highest law of an entity.  More specifically:

(a)  In corporate law, the articles of incorporation.

(b)  In public law, the instrument by which a municipality is incorporated (e.g., city charter).  This type of charter includes the highest laws of the municipality and its organizational structure.

(c)  In legislative law, a government act that establishes a publicly funded business or undertaking.

2.  In popular usage, the lease of a bus, airplane, ship, or other usually large or expensive vehicle for transporation.  A person who signs such a lease is said to charter the vehicle.  The vehicle used under this agreement is said to be chartered.