next to somebody/something and facing the same way 并列；并排；并肩 cycling two abreast 两人骑车并排而行 - abreast of somebody/something
A police car drew abreast of us and signalled us to stop. 一辆警车开过来与我们并行，示意我们停下来。
Word Originlate Middle English: from a- ‘in’ + breast.
Idioms
keep abreast of something
to make sure that you know all the most recent facts about a subject 了解最新情况；跟上（某事物的发展）