The prefix 'INSIDE' is used to describe something that is located WITHIN or INSIDE of something else. The prefix can be used in a variety of words, such as endo, ENTO, and intra. Endo is a four letter prefix meaning 'WITHIN, ' while ENTO is also a four letter prefix meaning 'WITHIN' or 'INSIDE.' Intra is a five letter prefix meaning 'WITHIN, ' 'INSIDE, ' or 'AMONG.' All three of these prefixes are used to describe something that is located WITHIN or INSIDE of something else.