Definition of inside:
(n) :
the interior or inner part; the side of a curved road, racetrack etc. that has the shorter arc length; the side of a racetrack nearer the interior of the course or some other point of reference
"the inside of the building has been extensively restored."
(preposition) :
within the
interior of something, closest to the center or to a specific point of reference; in prison
"he placed the letter inside the envelope."
(v) :
within or towards the
interior of something, especially a building
"it started raining, so I went inside."
(adj) :
originating from or arranged by someone inside an organisation; a pitch that is toward the batter as it crosses home plate
"the reporter had received inside information about the forthcoming takeover."