Rigor (noun)

1. The quality or state of being strict, severe, or harsh.
2. The quality or state of being inflexible or unyielding.
3. The quality or state of being extremely accurate, precise, or thorough.

Origin:

From latin rigor (stiffness, rigidity), from rigere (to be stiff or rigid).

Examples:

1. The new regulations have increased the rigor of the inspection process.
2. The rigor of the training program is designed to prepare students for the demands of the profession.
3. The scientific method requires a high degree of rigor in order to ensure accurate results.
4. The teacher's strictness and rigor were the reason why her class was so successful.
5. The company's rigor in quality control ensures that all products are of the highest standards.