psychosis

 
Pronunciation: /sʌɪˈkəʊsɪs/

noun (plural psychoses /-siːz/)

  • a severe mental disorder in which thought and emotions are so impaired that contact is lost with external reality: they were suffering from a psychosis [mass noun]: the symptoms of psychosis

Origin:

mid 19th century: from Greek psukhōsis 'animation', from psukhoō 'I give life to', from psukhē 'soul, mind'

Spelling rule

Make the plural of psychosis by changing the -is ending to -es: (psychoses).