fractionation

Etymology

From fraction + -ation or fractionate + -ion.

noun

1. (chemistry) 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.
   Methane is separated from other hydrocarbons in a gas fractionation plant.
2. (radiotherapy) The division of a total dose of radiation into fractions.
3. (cryptography) 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.