inside
n. countablen. the part that is on the inner side of something. You use it to talk about what is contained within a box, a building, or even a person's mind.
n. the inner part, surface, or interior of an object or space. Often used in the plural to refer to internal organs or the hidden workings of a machine.
The inside of the box is painted blue.
She cleaned the inside of the car until the leather seats looked brand new.
While the exterior of the cathedral appeared weathered and grey, the inside revealed a stunning display of gold leaf and vibrant stained glass.
From Middle English ynneside; equivalent to in- + side. Compare German Innenseite (“inside”), Danish inderside (“inside”), Swedish insida (“inside”), Dutch binnenzijde (“inside”), German Low German Binnensied, Binnersied (“inside”), Saterland Frisian Binnersiede (“inside”).
Commonly used with the preposition 'of' to specify the container or object.