Tandem, or in tandem, is an arrangement in which two or more animals, machines, or people are lined up one behind another, all facing in the same direction.[1] Tandem can also be used more generally to refer to any group of persons or objects working together, not necessarily in line.[1]
The English word tandem derives from the Latin adverb tandem, meaning at length or finally.[2] It is a word play, using the Latin phrase (referring to time, not position) for English "at length, lengthwise".[3]