iso-

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.

Nearby words

Also especially before a vowel, is-.

Origin of iso-

< Greek, combining form of ísos equal

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

British Dictionary definitions for iso-

iso-

before a vowel is-

combining form

equal or identicalisomagnetic

indicating that a chemical compound is an isomer of a specified compoundisobutane; isocyanic acid

Word Origin for iso-

from Greek isos equal

Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Word Origin and History for iso-

iso-

word-forming element meaning "equal, similar, identical; isometric," from comb. form of Greek isos "equal to, the same as" (e.g. isometor "like one's mother"). Used properly only with words of Greek origin; the Latin equivalent is equi- (see equi-).

Medicine definitions for iso-

iso-

pref.

Equal; uniform:isobar.

Isomeric:isopropyl.

Characterized by sameness with respect to species:isoantigen.

Characterized by sameness with respect to genotype:isograft.

Science definitions for iso-

iso-

A prefix that means equal, as in isometric, having equal measurements.

A prefix used to indicate an isomer of an organic compound, especially a branched isomer of a compound that normally consists of a straight chain. The isomer is characterized by a Y-shaped branch at the end of the chain that consists of two prongs. Each prong consists of one carbon atom. Thus isopentane contains five carbon atoms like normal pentane, but arranged as a chain of three carbons plus a Y-shaped branch of two carbons at the end.