Definition of inside:
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."
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."
within or towards the interior
of something, especially a building
"it started raining, so I went inside."
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."