What does rehydrate mean?
Rehydrate means to give water or another fluid again, restoring a person, organism, or substance to a hydrated state. People rehydrate after exercise, heat exposure, illness, or travel, while dried foods such as beans, fruit, and mushrooms are rehydrated by soaking or adding liquid. The word is also used transitively, as in “rehydrate the body,” and intransitively, as when a dried ingredient “rehydrates quickly.” Its prefix re- makes the meaning especially clear: it refers to returning something to a hydrated condition after water or moisture has been lost. Although “hydrate” is often used similarly in general speech, “rehydrate” more precisely suggests a second or renewed hydration. The term is widely understood in British and American English and is especially useful when describing both personal care and the preparation of previously dried materials.
To restore something to a hydrated state by supplying water or another fluid.
"Use an electrolyte drink to rehydrate after a long run."
This use is transitive and is common in health, sport, medical, and food contexts.
To become hydrated again after losing water or moisture.
"The dried seaweed rehydrates in cold water within a few minutes."
This intransitive use is especially common for dried foods and other materials that absorb liquid.
Rehydrate is the prefix-powered opposite of dehydration: when the water is back on the team, you are rehydrating.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of rehydrate
Rehydrate was formed in English by combining re-, meaning “again,” with hydrate. Hydrate ultimately comes from Greek hydōr, meaning “water,” and refers to combining a substance with water or restoring it to a moist condition. The prefixed form follows the established English pattern of forming a new verb by adding re- to an existing verb to indicate repetition or reversal of a prior state.
Related word forms
How rehydrate is actually used
Rehydrate is common in health, fitness, food, and household contexts. In medical writing, it often means restoring a patient's fluid balance, while in food preparation it describes reconstituting a dried ingredient.
Easily confused with rehydrate
To hydrate is to supply or absorb water, whereas to rehydrate is to do so again after dehydration or drying.
Dehydrate means to remove moisture or water from something, while rehydrate means to restore moisture or water to it.