I.S.O.

iso-,

combining form. equal; alike: »

Isometric = metrically equal. Isosceles = having two sides equal. Isothermal = having to do with equal temperatures. Isotope = any of two or more elements having the same place (on the periodic table of elements).

Also, is- before vowels.

╂[< Greek iso- < isos equal]

ISO (no periods) or I.S.O.,

International Standards Organization.