Around and round are prepositions or adverbs. We use around and round when we refer to movements in circles or from one place to another. Around and round can both be used. Around is more common in American English. Round is a little more common in speaking:
The earth goes round the sun. (movement in circles)
We spent a very pleasant day walking round the town. (movement from one place to another)
Now they are retired, they are planning a trip around the world.
We also commonly use around and round in phrasal verbs:
Can you pass these application forms around to all the people present?
We spent the whole day moving round some furniture in the bedroom.
Around and round also mean ‘in different places’ and ‘here and there’:
People were panicking and running round and shouting.
I know she’s around somewhere in the office.
Around can also mean ‘approximately’:
How old do you think the castle is?B:
I’d say around 500 years.