A textbook, a book designed to accompany a specific academic course, or one specified by the writers of the course to be read by its students.

Not following the planned, or intended, route.

Misspelling of of course.

plural of coursebook

(nautical) On a mizzenmast, the lowest sail

plural of golf course

(idiomatic) A natural or logical outcome. / (idiomatic) An expected or customary outcome.

simple past tense and past participle of course

There will always be problems in a romantic relationship.

(construction) A sacrificial material used to shield a waterproofing material from damaging external forces.