Invariability

in·var·i·a·ble  (n-vâr--bl)

adj.

Not changing or subject to change; constant.

---

in·vari·a·bili·ty, in·vari·a·ble·ness n.

in·vari·a·bly adv.

Thesaurus

Noun	1.	invariability - a quality of uniformity and lack of variation evenness regularity - the quality of being characterized by a fixed principle or rate; "he was famous for the regularity of his habits" smoothness - the quality of having a level and even surface; "the water was a glassy smoothness"; "the weather system of the Pacific is determined by the uninterrupted smoothness of the ocean" unevenness, variability - the quality of being uneven and lacking uniformity
	2.	invariability - the quality of being resistant to variation invariableness, invariance unchangeability, unchangeableness, unchangingness, changelessness - the quality of being unchangeable; having a marked tendency to remain unchanged unvariedness - characterized by an absence of variation variability, variableness, variance - the quality of being subject to variation