Answer:
Prefix
Step-by-step explanation:
A Prefix is defined as a morpheme or the part of the word that is added to the beginning of a root word to modify its meaning. This element of the word usually consists of 'a letter, a syllable, or several syllables' which primarily functions to either modify or revise the meaning of the base word. For example, if we place the prefix 'un-' before the base word 'happy', it becomes the antonym of the word and means 'not happy' while the prefix 'semi-' alters the meaning of the word by making it half like if 'semi-' is placed before circle, it means 'half circle.'