A prefix is a letter or group of letters added to the beginning of a word to change its meaning.

Quick Scoop: What is a Prefix?

Think of a prefix as a “mini-attachment” you clip to the front of a word so the word means something new.

You can’t usually use a prefix on its own; it needs a base (root) word to attach to.

Simple definition

  • A prefix is an affix (word part) placed before the stem or root of a word.
  • It changes the meaning of the original word, often by making it negative, opposite, repeated, or indicating time/position.
  • Common English prefixes include: un- , re- , dis- , pre- , bi- , sub-.

Quick examples

  • happy → un happy (adds a negative meaning “not happy”).
  • do → re do (adds “again”).
  • kind → un kind (opposite meaning).
  • view → pre view (“before” you see it officially).
  • cycle → bi cycle (“two” wheels).

What prefixes do to words

  • Make a meaning negative/opposite : un-, in-, dis- (e.g., unfair, incorrect, disagree).
  • Show time/order : pre- (“before”), post- (“after”), re- (“again”).
  • Show position : sub- (“under”), super- (“above”), trans- (“across”).
  • Show quantity : bi- (“two”), mono- (“one”), multi- (“many”).

Tiny story to remember it

Imagine the root word is a plain sandwich.
Every prefix is like a label you stick on the box: “un-” = “do the opposite,” “re-” = “do it again,” “pre-” = “before it’s served.”
The sandwich inside changes how people understand it, just because of that little label on the front.

One-sentence TL;DR

A prefix is a small word part added to the front of another word to give it a new or adjusted meaning, like turning “do” into “redo” or “fair” into “unfair.”

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