| A | B |
| intracellular | within the cells |
| intradermal | within the layers of the skin |
| intragalactic | within a galaxy |
| intramural | involving students within the same school |
| intranasal | within the nose |
| intraocular | within the eye |
| intrapersonal | existing or occurring within your own mind |
| intrapsychic | within the mind |
| intrastate | within the state |
| intravenous | within the veins |
| interactive | an exchange of activity or information between people or people and a computer |
| interfere | to get in between two people when it is not your problem or issue |
| interject | to throw a remark into a conversation between two or more people |
| intermission | the break between parts of a play |
| international | between or among the nations of the world |
| internet | the worldwide computer system that allows communication and information sharing among people |
| interpersonal | between people |
| interpreter | a person who helps translate the languages between different people |
| interrupt | to break into a conversation between people |
| interstate | between the states |