The state or condition of being inside.

The interior or inner part. / The left-hand side of a road if one drives on the left, or right-hand side if one drives on the right.

Of or pertaining to the inner surface, limit or boundary. / Nearer to the interior or centre of something. / Originating from, arranged by, or being someone inside an organisation.

Within or towards the interior of something; within the scope or limits of something (a place), especially a building. / (colloquial) In or to prison. / Indoors.

Within the interior of something, closest to the center or to a specific point of reference. / Within a period of time.

A person who has special knowledge about the inner workings of a group, organization, or institution. / A person who is within an enclosed space.

plural of inside

guts, intestines, innards

plural of insider

The quality of being an insider.