■ noun
1》 a bicycle with seats and pedals for two riders, one behind the other.
2》 a carriage driven by two animals harnessed one in front of the other.
3》 a group of two people or machines working together.
■ adverb one behind another.
Phrases
in ~
1》 alongside each other; together.
2》 one behind another.
Origin
C18: humorously from L., lit. 'at length'.