ISO

UK: /aɪsaʊ/ US: (ī′sō)

Collins Concise English Dictionary © HarperCollins Publishers::

ISO / ˈaɪsəʊ/ noun

1. International Organization for Standardization

Etymology: Greek isos equal; often wrongly thought to be an abbreviation for International Standards Organization

WordReference Random House Learner's Dictionary of American English © 2025

iso-, prefix. 

1. iso- comes from Greek, where it has the meaning "equal''. This meaning is found in such scientific and chemical words as: isosceles, isotope.

WordReference Random House Unabridged Dictionary of American English © 2025

i•so  (ī′sō), n., pl. -sos. [Television Slang.]

1. Radio and Television See isolated camera. 

• compare -o by shortening

ISO, 

1. Stock Exchange, Business incentive stock option.
2. Photography, International Standardization Organization.
3. Photography the numerical exposure index of a photographic film under the system adopted by the International Standardization Organization, used to indicate the light sensitivity of the film's emulsion.

iso-, 

1. a combining form meaning "equal,'' used in the formation of compound words:
   isochromatic;
   
   in chemistry, used in the names of substances which are isomeric with the substance denoted by the base word:
   isocyanic acid.

Also,[esp. before a vowel,] is-. 

• Greek, combining form of ísos equal

Collins Concise English Dictionary © HarperCollins Publishers::

iso-, (before a vowel)is- combining_form

1. equal or identical: isomagnetic
2. indicating that a chemical compound is an isomer of a specified compound: isobutane, isocyanic acid

Etymology: from Greek isos equal