/ ˈpriːfɪks; NAmE / noun , verb
■ noun
1.
( grammar ) a letter or group of letters added to the beginning of a word to change its meaning, such as un- in unhappy and pre- in preheat
—compare affix , suffix
2.
a word, letter or number that is put before another :
Car insurance policies have the prefix MC (for motor car).
3.
( old-fashioned ) a title such as Dr or Mrs used before a person's name
■ verb
[ vn ] prefix A to B | prefix B with A to add letters or numbers to the beginning of a word or number :
American members have the letters US prefixed to their code numbers.
Their code numbers are prefixed with US.
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WORD ORIGIN
mid 16th cent. (as a verb): from Old French prefixer , from Latin praefixus fixed in front, from the verb praefigere , from prae before + figere to fix. The noun is from modern Latin praefixum , neuter (used as a noun) of praefixus , and dates from the mid 17th cent.