Definitions

1. adverb

in a state of being side by side; at the same level or distance

“They walked abreast of each other along the beach.”

2. preposition

from one side to the other; from one end to the other

“The ship sailed abreast of the rocky coastline.”

3. verb

to be or place something at the same level or distance

“She abreasted her two horses to ride side by side.”