Betweenness

in the space separating (two points, objects, etc.):
between New York and Chicago.
intermediate to, in time, quantity, or degree:
between twelve and one o’clock; between 50 and 60 apples; between pink and red.
linking; connecting:
air service between cities.
in portions for each of (two people):
splitting the profits between them.
among:
sharing the responsibilities between the five of us.
by the dual or common action or participation of:
Between us, we can finish the job in a couple of hours.
distinguishing one from the other:
He couldn’t see the difference between good and bad.
in comparing:
no preference between the two wines.
by the combined effect of.
existing confidentially for:
We’ll keep this matter between the two of us.
involving; concerning:
war between nations; choice between things.
being felt jointly or reciprocated by:
the love between them.
by joint possession of:
Between them they own most of this company.
Heraldry. in the midst of, so as to make a symmetrical composition:
a cross argent between four bezants.
Usually, betweens. a short needle with a rounded eye and a sharp point, used for fine hand stitchery in heavy fabric.
in the intervening space or time; in an intermediate position or relation:
two windows with a door between; visits that were far between.
between ourselves, confidentially; in trust.
Also, between you and me, between you, me, and the post/lamppost/gatepost/etc.
in between,

situated in an intermediary area or on a line or imaginary line connecting two points, things, etc.
in the way:
I reached for the ball, but the dog got in between.

preposition
at a point or in a region intermediate to two other points in space, times, degrees, etc
in combination; together: between them, they saved enough money to buy a car
confined or restricted to: between you and me
indicating a reciprocal relation or comparison: an argument between a man and his wife
indicating two or more alternatives: a choice between going now and staying all night
adverb
between one specified thing and another: two houses with a garage between
n.
prep.

between a rock and a hard place
between the lines
between you and me