Diligence (noun)

1. Careful and persistent effort to accomplish a task.
2. Diligent attention to one's responsibilities.

Origin:

Middle english: from old french diligence, from latin diligentia, from diligent- "having care and zeal", from the verb diligere.

Examples:

1. The investigation was conducted with great diligence.
2. The diligence of the detectives led to the capture of the criminal.
3. Her diligence in studying paid off when she got an A on the test.
4. The diligence of the workers was impressive and the project was completed on schedule.
5. The diligence of the researchers led to a breakthrough in the field.