inside

(not comparable)Within or towards the interior of something; within the scope or limits of a place, especially a building.

I opened the book and found a hidden note inside.

It started raining, so I went inside.

within a building

Within or towards the interior of something; within the scope or limits of a place, especially a building.

(not comparable)Indoors.

It was snowing, so the children stayed inside.

(not comparable)On the inner side of something.

I cleaned the window inside.

(colloquial, not comparable)In or to prison.

He spent ten years inside, doing a stretch for burglary.

She will have to go inside unless the jury sides with her.

(not comparable)Intimately, secretly or in one's inner heart or soul; without expressing what one is feeling or thinking.

That's something I truly believe inside.

He knows the truth, but he's keeping it inside.