I. in ‧ side 1 S2 W2 /ɪnˈsaɪd/ BrE AmE adverb , preposition
1 . CONTAINER in or into a container or other closed space so as to be completely covered or surrounded OPP outside :
The jewels were locked away inside the safe.
I sent the money inside an envelope addressed to Ann.
Carl picked up the book and stuffed it inside his jacket.
Her car was locked and the keys were inside.
2 . BUILDING/ROOM in or into a building or room OPP outside :
It’s raining. We’ll have to go inside.
She could hear voices inside, but no one came to the door.
Mail was piled up just inside the doorway.
The sound was coming from inside the house.
inside of American English :
There were 20 people packed inside of her dorm room.
3 . COUNTRY/AREA in a country or area – used when you want to emphasize that something is happening there and not in other places OPP outside :
Very little is known of events inside this mysterious country.
The guerrillas were said to be operating from bases inside the war zone.
4 . ORGANIZATION if someone is inside a group or organization, they are part of it OPP outside :
women’s influence inside the party
The information comes from sources inside the company.
Discussions should involve local people both inside and outside the school.
5 . HEAD/MIND if something happens inside you, or inside your head or mind, it is part of what you think and feel, especially when you do not express it:
You just don’t understand how I feel inside!
Steve’s a strange guy – you never know what’s going on inside his head.
Anger bubbled up deep inside her.
inside of American English :
Something inside of me told me not to trust him.
6 . BODY in your body:
She could feel the baby kicking inside her.
You’ll feel better once you’ve got a good meal inside you (=after you have eaten something) .
7 . TIME
a) in less than a particular amount of time:
A full report is expected inside three months.
inside the hour/month etc (=before an hour, month etc has passed)
We’ll be back inside the hour.
inside of especially American English :
Our aim is to get the whole job finished inside of a week.
b) less than a particular amount of time OPP outside :
Jonson’s time of 9.3 seconds was just inside the world record.
8 . PRISON informal in prison:
My boyfriend’s been inside for a year.
II. in ‧ side 2 S3 /ɪnˈsaɪd, ˈɪnsaɪd/ BrE AmE noun
1 . the inside the inner part of something, which is surrounded or hidden by the outer part OPP the outside
on the inside
The apple’s rotten on the inside.
the inside of
condensation on the inside of the window
The door had been locked from the inside.
2 . inside out with the usual outside parts on the inside:
You’ve got that jumper inside out.
Her umbrella blew inside out.
I always turn my jeans inside out to wash them.
3 . turn a room/building etc inside out to search a place very thoroughly by moving everything that is in it:
The drug squad turned the apartment inside out.
4 . know something inside out British English , know something inside and out American English to know something in great detail:
She knows her subject inside out.
5 . on the inside someone who is on the inside is a member of a group or an organization:
Someone on the inside must have helped with the robbery.
6 . on the inside British English if a car passes another car on the inside, it passes on the side that is away from the driver
7 . sb’s inside/insides informal someone’s stomach:
My insides are beginning to complain about the lack of food.
III. in ‧ side 3 /ˈɪnsaɪd/ BrE AmE adjective
1 . in or facing the inner part of something:
the inside pages of the newspaper
the inside pocket of his jacket
2 . inside information/the inside story etc information that is available only to people who are part of a particular group or organization:
Police believe the robbers may have had inside information.
3 . the inside lane British English the ↑ lane that is furthest away from the middle of the road OPP outside lane