Meaning of “up” - Learner’s Dictionary

up

adverb, preposition uk us /ʌp/
HIGHER PLACE

A2 towards or in a higher place:

He ran up the stairs.
Pick up your clothes and put them away.
She looked up and smiled at me.
VERTICAL

A1 vertical or as straight as possible:

He stood up.
She opened her eyes and sat up.
INCREASE

B2 to a greater degree, amount, volume, etc:

Inflation keeps pushing prices up.
Can you turn up the heat? I'm freezing!
Please speak up (= speak louder), I can't hear you.
COMPLETELY

B2 used to emphasize that someone completes an action or uses all of something:

I used up all my money.
Eat up the rest of your dinner.
up the road/street, etc

A2 along or further along the street/road, etc:

My best friend lives up the street from me.
He ran up the path and hugged her.
go/walk, etc up to sb/sth

B1 to walk directly towards someone or something until you are next to them:

He walked straight up to me and introduced himself.
DIRECTION

in or towards a particular direction, usually north:

We moved from London up to Scotland.
Chris lives up north.
up and down

B2 If something or someone moves up and down, they move repeatedly in one direction and then in the opposite direction:

The children were constantly running up and down the stairs.
up to 10/20, etc

B1 any amount under 10/20, etc:

We can invite up to 65 people.
up to

B1 until a particular time:

You can call me up to midnight.
up to sth

equal in quality or achievement:

His work wasn't up to his usual standard.
up to sth/doing sth

able to do something:

It'll be a while before I feel up to walking again.
be up to sth informal

B1 to be doing or planning something, often something secret and bad:

Joe, what are you up to?
be up to sb

B1 If an action or decision is up to someone, they are responsible for doing or making it:

I can't decide for you Jack, it's up to you.
[ + to do sth ] It's up to her to decide whether she wants to enter the competition.
be up against sb/sth

If you are up against a situation or a person, they make it very difficult for you to achieve what you want to achieve:

We were up against some of the best players in the world.

(Definition of “up adverb, preposition” from the Cambridge Learner’s Dictionary © Cambridge University Press)