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| Root | Meaning in English | Origin language | Etymology (root origin) | English examples | 
|---|---|---|---|---|
| ichthy- | fish | Greek | ἰχθύς (ichthus) | ichthyology | 
| icos- | twenty | Greek | εἴκοσι (eikosi) | icosagon, icosahedron | 
| id- | shape | Greek | εἶδος (eidos) | idol | 
| ide- | idea; thought | Greek | ιδέα (idea) | ideogram, ideology | 
| idi- | personal | Greek | ἴδιος (idios) | idiom, idiosyncrasy, idiot | 
| ign- | fire | Latin | ignis | igneous, ignition | 
| in- (1), im- | in, on | Latin | in | import, incur, intend, invite | 
| in- (2), il-, im-, ir- | not, un- (negation) | Latin | in- | illicit, impossible, inimical, irrational | 
| infra- | below, under | Latin | infra | infrastructure | 
| insul- | island | Latin | insula | insular, insulation | 
| inter- | among, between | Latin | inter (preposition) | intercollegiate, intermission, intersection | 
| intra- | within | Latin | intra | intramural | 
| irasc-, irat- | be angry | Latin | irasci | irascible, irate | 
| is-, iso- | equal, the same | Greek | ἴσος (isos) | isometric, isomorphic, isotropic | 
| iter- | again | Latin | iterum, iterare | iteration | 
| itiner- | route, way | Latin | iter, itineris – march, journey | itinerary | 
Read more about this topic: List Of Greek And Latin Roots In English