Definition of peta- in US English:

peta-

combining form

  • (used in units of measurement) denoting a factor of 10¹⁵ (one thousand million million)

    ‘petabytes’

Origin

From pe(n)ta- (see penta-), based on the supposed analogy of tera- and tetra-.

Pronunciation

peta-

/ˈpetə-/