thick rope; hawser
Refers to a physically thick, heavy rope, often used in nautical or construction contexts.
They used a thick rope to secure the ship to the shore.
fundamental principles; outline; general features
Figurative use: the essential framework or broad outline of a plan, policy, or concept. Often used in formal or political contexts.
The outline of the new policy was announced.
Compound of 大 (おお, 'big') and 綱 (つな, 'rope'). The figurative sense 'outline' derives from the idea of a main rope that holds things together.