n. & adv.
--n.
1. a bicycle or tricycle with two or more seats one behind another.
2 a group of two persons or machines etc. with one behind or following the other.
3 a carriage driven tandem.
--adv. with two or more horses harnessed one behind another (drive tandem).
Phrases and idioms:
in tandem one behind another.
Etymology: L, at length (of time), used punningly