Prefixes are the letters added to the front of a root word to change its meaning or function. E.g., happy – unhappy. The prefix ‘a’ means ‘on’, ‘in’, or ‘up’ See the following word formed with this prefix. Shore – ashore. Al’ means all. The word ‘most’ can be changed into ‘almost’ by using the prefix ‘al’.
Auto’ means ‘self’. Biography is the life story of a person written by someone else, whereas an autobiography is a book about a person's life, written by the person himself/ herself. The prefix ‘be’ means make or cause a thing. We can change the meaning of the word little by adding the prefix ‘be’. For example, little – belittle (to make someone, or things that someone does, seem unimportant)
Several similar prefixes will change the meaning of a given word into negative one. See how the prefix ‘un’ changes the meaning of the word common.‘Un’ = ‘not’ Common means found everywhere where as uncommon would mean very rare.