Definition of in theory in US English:

in theory


  • Used in describing what is supposed to happen or be possible, usually with the implication that it does not in fact happen.

    ‘in theory, things can only get better; in practice, they may well become a lot worse’
    • ‘Working on Saturdays is always confusing because we start earlier and, in theory, end earlier.’
    • ‘In theory it may seem like a great idea but, in theory, so do so many ideas until they are put into practice.’
    • ‘The Freedom of Information Act is, in theory, a way of ensuring that happens.’
    • ‘Radar also uses microwaves, so that in theory it would be possible to cook food by putting it at the focus of a radar dish.’
    • ‘While in theory that's an admirable trait, in practice it's pretty uncomfortable.’
    • ‘This concept, though brilliant in theory, is utterly, utterly painful in practice.’
    • ‘However, although this sounds good in theory, in practice it never quite seems to work that way.’
    • ‘The precautionary principle sounds good in theory, but in practice it is a nightmare.’
    • ‘The software makes it possible, in theory, to see and manage files on any storage system or server.’
    • ‘These are ideas which are beautiful in theory but limp and bedraggled in practice.’
    in principle, on paper, in the abstract, all things being equal, in an ideal world
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