say it: in-VER-ee-uh-buhl
invariable is a noun and adjective meaning "a quantity that does not vary". It carries 2 recorded senses.
a quantity that does not vary
not liable to or capable of change
“an invariable temperature”
“an invariable rule”
“his invariable courtesy”
Forms marked · are formed by the regular rule rather than recorded in the source data. English keeps a few hundred irregulars and the rest follow the pattern, so the rule is right far more often than not — but it is a rule, and the mark says so.
Definitions, synonyms and semantic relations for invariable come from Princeton University’s WordNet. The pronunciation comes from the CMU Pronouncing Dictionary. Commonness is measured against a corpus of everyday English. Full sources and licences.