say it: in-val-uh-DAY-shuhn
invalidation is a noun meaning "(law) a formal termination (of a relationship or a judicial proceeding etc)". It carries one recorded sense.
(law) a formal termination (of a relationship or a judicial proceeding etc)
law
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 invalidation 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.