Definition of flatten out in US English:

flatten out

phrasal verb

  • 1(of an increasing quantity or rate) show a less marked rise; slow down.

    • ‘Eating at shorter intervals will also help flatten out excessive rises and dips in your blood sugar, which means you'll have energy available for use more consistently.’
    • ‘That asymptotic rise of the stock markets since WWII has flattened out.’
    • ‘If you're a retailer, for example, the hosting bills will likely surge during the holiday season but then flatten out during slow months.’
    • ‘On the other hand, the survey report will point out that the recent fall in unemployment is slowing, effectively flattening out over the past three months.’
    • ‘However, this rate has flattened out in the past decade, although women's educational level continues to grow steadily.’
    • ‘The long ‘plateau’ period where this rise in prosecutions flattened out is more difficult to explain.’
    • ‘Both these trends have flattened out in recent years, with the rate increasing slightly in 1999 and 2000.’
    • ‘There was, as a result, no financial and industrial bankruptcy, but growth rates flattened out for the rest of the period, until they were restarted by the outbreak of the First World War.’
    • ‘Despite an ongoing economic boom, Portland's housing cost increases flattened out after 1995, and now roughly match the rate of inflation.’
    • ‘We saw prices rise by about five or six per cent and the market flattened out a lot.’
  • 2Make an aircraft fly horizontally after a dive or climb.

    ‘he flattened out and made a fine three-point landing’
    • ‘The Ju 88 went into a steep, jinking dive with the rear gunner firing at the other members of his Section who all attacked, until the Ju 88 flattened out and crash-landed at high speed.’
    • ‘People out fishing reported seeing the aircraft flying straight and level, then entering a spiral dive before flattening out momentarily.’