around, a round

Around or around ( one word ) is an informal word for approximately, or in the neighborhood or area of--
I'll be back around 8 o' clock.
Don't hang around the house all day; go out and play.
He lives somewhere around 84th Street.

Around may mean to do something that has been on a list or waiting for your attention--
I'll do that when I get around to it.

Around or around also means in a circle or surrounding a center point, or to move in a circle--
We all gathered around the fire to tell stories.
A crowd gathered around, but the police stopped them before they could get close.
He turned around, and what a surprise!

Around may mean to make a detour so as to avoid; to get past a difficulty--
We got stuck in traffic, waiting get around a stalled car.
We can get around the new regulations by changing the name of our product.

Around may also mean in circumference, when measured--
The tree is about three feet around, at the base.
Use a piece of string to measure around the pole.

A round or a round ( two words ) describes something that is circular or spherical in shape--
She wants a round mirror, to use as a tray on the dresser.
Can you cut a round piece of glass to fix a window?

A round may also mean a part of a boxing match, a game of golf, or a part of some other game--
How about a round of golf?
We are going next door to play a round of bridge.
A round may mean a set of drinks, one for each person--
The man at the end of the bar wants to buy a round of drinks.

A round may mean a song sung by different persons or groups, as a sort of relay--
We could sing this as a round, to make it more interesting.

Now that you know that, you can say--
"I told them to meet us around seven, for a round of drinks and then dinner."