say it: dee-hahy-DRAY-shuhn
dehydration is a noun meaning "dryness resulting from the removal of water". It carries 3 recorded senses.
dryness resulting from the removal of water
depletion of bodily fluids
the process of extracting moisture
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 dehydration 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.