Meaning:
A condition of being strictly accurate or severe

Explanation:
Rigor refers to a state of being thorough, exact, and strict in method or execution. It can also describe harsh or severe conditions. In academics, it often describes high levels of scrutiny or strict standards during research, testing, or analysis. In medicine, it is used to describe a sudden and intense condition such as rigor mortis, the stiffening of the body muscles that occurs after death.

History:
From the Old French word 'rigor', or 'rigour', and also from the Latin 'rigor,' which means 'cold' or 'numbness'. The medical term originates from these same Latin roots, referencing the cold stiffening that characterizes the post-mortem state.