1. A quality of uniformity and lack of variation
   "The invariability of the machine's output made it ideal for mass production";
   - evenness
    
2. The quality of being resistant to variation
   "The invariability of the speed of light in a vacuum is a cornerstone of modern physics";
   - invariableness, invariance

Derived forms: invariabilities

See also: even, uneven

Type of: changelessness, regularity, unchangeability, unchangeableness, unchangingness

Antonym: variability