prefix
noun /ˈpriːfɪks/
  /ˈpriːfɪks/
 - (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
- negative prefixes such as ‘un-’ and ‘dis-’
 
 - a word, letter or number that is put before another
- Car insurance policies have the prefix MC (for motor car).
 
 - (old-fashioned) a title such as Dr or Mrs used before a person’s nameTopics Family and relationshipsc2
 
Word Originmid 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.