fractionation

noun

Etymology: By surface analysis, fraction + -ation, or, by surface analysis, fractionate + -ion.

1. A separation process in which a certain quantity of a mixture is divided up into smaller quantities (fractions) in which the composition changes according to a gradient; an instance of this process.

   “Methane is separated from other hydrocarbons in a gas fractionation plant.”

   “After several fractionations, we had a usable product.”

2. The division of a total dose of radiation into fractions.
3. A preliminary stage of encryption that divides each plaintext symbol into several ciphertext symbols.
4. A form of hypnosis where the patient is made to enter and leave a trance state many times in quick succession.