in

In means inside the area, moving from a point outside to point inside or having a specific occupation or function. (preposition)

In means to go from outside to inside. (adverb)

An example of in is to walk into a house from the backyard.

In means successful or powerful. (adjective)

An example of in is are people who are the most looked-up to or the most fashionable.

See in in Webster's New World College Dictionary

contained or enclosed by; inside; within: in the room, in the envelope
wearing; clothed by: to dress in one's best
during the course of: done in a day
at or before the end of: return in an hour
perceptible to (one of the senses): the town is in sight; he told a lie in my hearing
limited by the scope of: in my opinion
1. being a member of or worker at: in the navy, in business
2. being a student at: she's in college
3. being an inmate of: to be in prison
out of a group or set of: one in ten will fail
amidst; surrounded by: in a storm, in total darkness
affected by (a specified state or condition); having: he's in trouble; they were in tears
engaged or occupied by (an activity or process): in a search for truth, deep in thought
with regard to; as concerns: weak in faith, to vary in size, six feet two in height
so as to form; arranged to produce the form or shape of: hair done in curls, standing in a line
with; by; using: to paint in oils, written in English, sculpture done in wood
because of; for: to cry in pain
by way of; for the purpose of: do this in my defense
as a part of the capacity or function of; belonging to: he didn't have it in him to cheat; can you find it in yourself to forgive her?
into [break it in two; come in the house]: when the idea of motion from outside to inside is intended, into is generally preferred
living or located at: vacationing in Venice

adverb

from a point outside to one inside: to invite visitors in
to or toward a certain place or direction: he flies in today, they live ten miles in
at or inside one's home, office, etc.: forced to stay in for a day
1. so as to be contained by a certain space or condition
2. so as to be in office or power
so as to be agreeing or involved: he fell in with our plans
so as to form a part: mix in the cream

adjective

that is successful or in power: the in group
inner; inside
coming or going inside or inward: the in door, the in boat
completed, gathered, counted, etc.: the votes are in
Informal profiting to the extent of: to be in $100
Informal currently smart, popular, fashionable, etc.: an in place to go
Informal known to or able to be understood by only a certain group of people; inside (): an in joke

noun

a person, group, etc. that is in power, in office, or in a favored position: usually used in pl.
☆ Informal special influence or favor; pull

transitive verb inned, inning

inch(es)

Indiana

indium

Indiana

See in in American Heritage Dictionary 4

(ĭn)

preposition

a. Within the limits, bounds, or area of: was hit in the face; born in the spring; a chair in the garden.
b. From the outside to a point within; into: threw the letter in the wastebasket.
To or at a situation or condition of: was split in two; in debt; a woman in love.
a. Having the activity, occupation, or function of: a life in politics; the officer in command.
b. During the act or process of: tripped in racing for the bus.
a. With the arrangement or order of: fabric that fell in luxuriant folds; arranged to purchase the car in equal payments.
b. After the style or form of: a poem in iambic pentameter.
With the characteristic, attribute, or property of: a tall man in an overcoat.
a. By means of: paid in cash.
b. Made with or through the medium of: a statue in bronze; a note written in German.
With the aim or purpose of: followed in pursuit.
With reference to: six inches in depth; has faith in your judgment.
Used to indicate the second and larger term of a ratio or proportion: saved only one in ten.

adverb

To or toward the inside: opened the door and stepped in.
To or toward a destination or goal: The mob closed in.
Sports So as to score, as by crossing home plate in baseball: singled the runner in.
Within a place, as of business or residence: The manager is in before anyone else.
So as to be available or under one's control: We can proceed when all the evidence is in.
So as to include or incorporate: Fold in the egg whites.
So as to occupy a position of success or favor: campaigned hard and was voted in.
In a particular relationship: got in bad with their supervisor.

adjective

Located inside; inner.
Incoming; inward: took the in bus.
Holding office; having power: the in party.
Informal
a. Currently fashionable: the in thing to wear this season.
b. Concerned with or attuned to the latest fashions: the in crowd. See Synonyms at fashionable.
Relating to, understandable to, or coming from an exclusive group: an in reference.