Definition of plain English in English:

plain English

noun

mass noun
  • Clear and unambiguous language, without the use of technical or difficult terms.

    ‘the family is given a written explanation in plain English’
    • ‘We have tried our best to speak in plain English and avoid police jargon so that it is clear what we want the organisation and everyone in it to do.’
    • ‘Can somebody here tell me, in plain English, what fair use law is?’
    • ‘What is meant here, in plain English, is "Don't trust the eyewitness accounts."’
    • ‘Then there are businesses that simply can't say anything at all in plain English and you simply do not know what it is they actually do.’
    • ‘They have developed a debugging program that lets users ask questions about computer errors in plain English.’
    • ‘The report includes several examples of how a contract can be rewritten in plain English.’