These prefixes tell where something is. inter- means “between” or “among”: an international game is played between nations, and to interrupt is to break in between. intro- (and intra-) means “within”: to introduce is to lead someone in. circum- and Greek peri- mean “around”: a circumference goes around a circle, and a perimeter measures around a shape.
Key idea
inter- = between, among. intro-, intra- = within, inward. circum- and peri- = around.
The parts and their words
Words taken apart
| Word and meaning | Parts, and what they say |
|---|---|
| interject to break in with a remark | inter- between + ject throw → “throw in between” |
| intermittent stopping and starting | inter- between + mitt let go + -ent → “letting go in between” |
| interlocutor a person taking part in a conversation | inter- between + locut speak + -or one who → “one who speaks between (in a conversation)” |
| introspective looking inward at one’s own thoughts and feelings | intro- within + spect look + -ive → “looking within” |
| circumspect careful to consider all risks before acting | circum- around + spect look → “looking around” |
| circumlocution using many words to avoid saying something directly | circum- around + locut speak + -ion → “speaking around (the point)” |
| peripheral at the edge; of minor importance | peri- around + pher carry + -al → “carried around (at the edge)” |
| interrupt to stop someone by breaking in | inter- between + rupt break → “break in between” |
Worked example: Between or within?
An interstate highway and an intrastate bus route: which one stays inside a single state?
- inter- means between: an interstate highway runs between states.
- intra- means within: an intrastate route stays within one state.
Answer: The intrastate route.
Meet the word
Common mistake
Mixing up inter- (between) and intra- or intro- (within). Interstate travel crosses from one state to another; intrastate travel stays inside one. An introspective person looks within, at their own thoughts, not between people.
A circumlocution “talks around” the point (circum-, around + locut, speak). Asked whether he broke the vase, a boy who says, “Well, objects in a house can sometimes move in unexpected ways…” is using circumlocution.