The word "about" is similar to the word "almost." Something is on the verge of happening, or it’s right up to the point of happening.
We were just about to leave.
The plane is about to land.
He’s just about to make an announcement.
The sun is just about to set.
Notice in the sentences above, the word "to" follows "about." There’s some activity that is soon to happen.
In this next set of examples, the word "about" is used with numbers and amounts:
She’s about seventy years old. (She’s almost 70 or around the age of 70.)
This weighs about a pound.
I’ll see you at about 10:00.
The meeting lasted about an hour.
A new Tesla costs about $50,000.
We also use "about" when discussing subjects and topics:
What is the movie about?
What do you want to talk about?
He has a lot to say about this subject.
Why did she lie about that?
There are many things to learn about in school.
Let’s talk about this.
We need to make a decision about this.
What is he reading about?
There are some recent uses for the word "about" that you should know. Look at the examples below:
I’m all about being fair.
Our mission is all about helping the poor.
She’s all about her friends.
Joe is all about himself.
It’s all about him.
The President makes everything about himself. It’s always me, me, me.
In these examples, when a person is "all about" something, the focus is on that thing exclusive to other things or people. This can be good or bad, depending on the situation.
Then there are other somewhat idiomatic uses for "about."
How did this come about? (How did this happen?)
There was a turn about in expectations. (Things changed.)
Turn about is fair play. (There is some amount of fairness in revenge or retaliation.)
He’s the man about town. (He’s very popular and he goes to many places locally.)