Origin: Latin prefix pre-
Prefix has 5 different meanings across 2 categories:
an affix that is added in front of the word
"The prefix un- was added to the beginning of happy to create unhappy."
Something placed before another
"The prefix pre- indicates that an action happens before another event."
A morpheme added to the beginning of a word to modify its meaning, for example as, pre- in prefix, con- in conjure, re- in reheat, etc.
"The teacher explained that adding the prefix un- to do creates the new verb undo, which changes the original meaning completely."
In plain English: A prefix is a group of letters you add to the beginning of a word to change its meaning.
"The teacher explained that adding a prefix like un- can completely change the meaning of a word."
Usage: A prefix is an affix attached directly to the front of a base word to change its meaning or grammatical form. You will often see it written with a hyphen when combining words, such as pre-order or re-sign, though many common prefixes like un- and dis- are fused without one.
To determine beforehand; to set in advance.
"The teacher gave us a prefix about the reading assignment so we could prepare our questions ahead of time."
In plain English: To prefix something means to add it before other things, usually as an introduction or lead-in.
"The editor decided to prefix his name to every letter he sent out."
The word comes from Late Latin praefīxum, meaning something fixed or set in front. It is formed by combining the idea of "before" with the act of fixing or fastening.