Abreast (adverb)

1. Side by side with.
2. Next to one another.

Origin:

From old english meaning "alongside".

Examples:

1. They walked abreast down the street.
2. Two cars can pass each other safely if they are abreast.
3. The two friends sat abreast on the park bench.
4. The soldiers stood abreast in formation.
5. The swimmers were instructed to stay abreast of the boat.