noun

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