direct

The root direct comes from Latin dīrectus, "set straight, made straight," the past participle of dīrigere — to guide something into a straight line. Pull dīrigere apart and you find dis- (apart, in separate directions) + regere (to rule, to keep straight). So at heart, to direct is to take something and aim it on a straight, intended course — whether that's an arrow, a letter, a film, or a person's attention.

This single image of "making straight / aiming" runs through the whole family:

- direct + -ly → directly: in a straight line, with nothing in between; also "immediately"
- direct + -ory → directory: a guide that points you straight to a name, address, or file
- re- (again, back) + direct → redirect: to aim something onto a new course
- in- (not) + direct → indirect: not straight — roundabout, going through intermediate steps

Notice how each prefix bends the same straight line: directly keeps it straight, indirect denies it, redirect re-aims it. The root stays put; the prefix decides what happens to the path.

One member arrives by a longer, more worn road. redress looks unrelated, but it traces back to the same dīrectus. Old French dresser meant "to set straight, arrange" (from Vulgar Latin *directiāre, "to make straight"), and re- + dresser gave redresser, "to set straight again." So when you seek redress for a wrong, you are literally asking for the crooked situation to be made straight once more — the same straightening image as direct, just carried in through French and disguised by spelling. (The everyday word dress, "to arrange/clothe oneself," comes from the same source.)

The lesson of this root: every direct word is about a straight path or a true aim, and the prefixes simply tell you what is being done to that path.