The word about can be used in the following ways.

As a preposition

When used as a preposition, about is followed by a noun which acts as its object.

• He doesn’t like to talk about his problem.
• We had a long discussion about music and movies.

As a preposition, about means concerning a particular subject

• I got angry when she said nasty things about my mother.
• She is worried about her health.
• We are talking about your studies.

As an adverb

About is not followed by a noun when it is used as an adverb.

• Children usually rush about.

About to

About can be followed by an infinitive with to.

When you are about to do something, you are just going to do it.

• I was about to have lunch.
• We were about to leave.

In spoken English, about is often used for introducing a subject that you want to discuss.

• About that money I owe you – I should be able to pay you back next week.
• It’s about your son – he’s been misbehaving in class lately.

About is also used for showing that you are guessing at an amount or number.

• About 50 members attended the conference.
• She must be about thirty-five.

About can be used for showing movement.

• The children were playing about the garden.

About can also be used to talk about position in many different parts or areas.

• He would always leave important papers lying about on his desk and then spend hours searching for them.