Rehydration rhymes with:
dehydration, dehydration, hydration, dehydration, hydration, dehydration, hydration, administration, arbitration, calibration, castration, celebration, concentration, conflagration, consecration, dehydration, demonstration, desecration, disintegration, duration, emigration, filtration, frustration, gyration, hydration, illustration, immigration, infiltration, integration, libration, migration, ministration, narration, nitration, oration, orchestration, penetration, proration, prostration, registration, sequestration, vibration
Rehydration sounds like:
reiteration, retardation, rotterdam