A rutter is a book that has information about sailing, like maps and where to find food and water.
A rutter is important for sailors to stay safe and find their way.
Examples:
The sailor used the rutter to find the best way to go.
I read the rutter to learn about the sea.
The rutter has a map of the ocean.
The rutter is the best book for sailors.
The rutter has all the secrets of the sea.
The rutter is the most important book on the ship.