in·side 
(ĭn-sīd, ĭnsīd′)
(ĭn-sīd, ĭnsīd′)n.
1.
a. An inner or interior part.
b. Inward character, perceptions, or feelings: felt good on the inside about volunteering to help.
2. An inner side or surface.
3. The part away from the edge; the middle part.
4. insides Informal
a. The inner organs; entrails.
b. The inner parts or workings: the insides of a TV set.
5. Slang Confidential or secret information.
adj.
1. Inner; interior.
2. Relating to, known to, or coming from an exclusive group: inside information; an inside joke.
3. Baseball Passing on the side of home plate nearer the batter. Used of a pitch.
adv.
1. Into or in the interior; within.
2. On the inner side.
3. Slang In prison.
prep.
Idioms: 1. Within: We'll be there inside an hour.
2.
a. On the inner side or part of: inside the package.
b. Into the interior of: going inside the house.
inside out
1. With the inner surface turned out; reversed: wore the sweatshirt inside out.
2. Informal As completely as possible; thoroughly: knew the city inside out.
on the inside
In a position of confidence or influence.