1. A group of letters that are added to the beginning of a word to modify its meaning: An example of a prefix is "un-" which when added to the word "happy" forms the term "unhappy".

Another prefix is "non-" added to "binding" which equals "nonbinding" or something which does not legally require that a person be forced to do anything; such as, a "nonbinding agreement".

2. A title that is placed in front of a person's name: "Dr. Smith", "Mrs. Jones" and "Mr. Smith" all demonstrate prefixes.

1. To put or to attach something before or in front of another element: When Joe Rogers completed his medical training, he was allowed to prefix his name as "Dr. Joe Rogers".

The author wrote a preface which was prefixed at the beginning of his book.

2. To settle or to arrange in advance: The manager of the store in New York made sure his employees prefixed the items with the correct $ amount and the ¢ suffix when it was applicable, for example when a shirt was on sale for $5.50¢ (5 dollars and 50 cents).
3. In grammar and vocabulary, to add part of a word to the front of another a word: To prefix "dis" in front of "believe" results in "disbelieve".