Definition of micro- in US English:

micro-

combining form

  • 1Small.

    ‘microcar’
    1. 1.1 Of reduced or restricted size.
      ‘microdot’
      ‘microprocessor’
  • 2(used commonly in units of measurement) denoting a factor of one millionth (10⁻⁶)

    ‘microfarad’

Origin

From Greek mikros ‘small’.

Pronunciation

micro-

/ˈmīkrō//ˈmaɪkroʊ/