Course of employment is a legal consideration of all circumstances which may occur in the performance of a person's job, especially during a period of time where specific objectives are given by the employer to the employee. Black's Law Dictionary (2nd Pocket ed. 2001) pg. 154.

Key examples of this consideration under US law can include tort

Tort

A tort, in common law jurisdictions, is a wrong that involves a breach of a civil duty owed to someone else. It is differentiated from a crime, which involves a breach of a duty owed to society in general...

 liability

Legal liability

Legal liability is the legal bound obligation to pay debts.* In law a person is said to be legally liable when they are financially and legally responsible for something. Legal liability concerns both civil law and criminal law. See Strict liability. Under English law, with the passing of the Theft...

 or ownership

Ownership

Ownership is the state or fact of exclusive rights and control over property, which may be an object, land/real estate or intellectual property. Ownership involves multiple rights, collectively referred to as title, which may be separated and held by different parties. The concept of ownership has...

 of intellectual property

Intellectual property

Intellectual property is a term referring to a number of distinct types of creations of the mind for which a set of exclusive rights are recognized—and the corresponding fields of law...

. If an employee is driving a motor vehicle during working hours and harms the person or property of another, a court would consider course of employment to determine if the employer had vicarious liability

Vicarious liability

Vicarious liability is a form of strict, secondary liability that arises under the common law doctrine of agency – respondeat superior – the responsibility of the superior for the acts of their subordinate, or, in a broader sense, the responsibility of any third party that had the "right, ability...

 for the harm. Extreme examples would likely find the employer is liable for a truck driver on his assigned route but not for a secretary picking up her child from day care.

Similarly the employer would likely own the copyright

Copyright

Copyright is a legal concept, enacted by most governments, giving the creator of an original work exclusive rights to it, usually for a limited time...

rights to a song written by an employee who was hired as a composer, but not if the employee was hired as an accountant.