It’s an enduring belief that between should be used in preambles of contracts with only two parties and among should be used in preambles of contracts with three or more parties. As legal usage scholar Bryan Garner quips, this is a superstition.
Between should be used when the relationship involves specific parties dealing distinctly with each other. Among should be used for general groupings that have only vague relations to one another.
As Fowler puts it (quoting the Oxford English Dictionary), between “is still the only word available to express the relation of a thing to many surrounding things severally and individually”, while among expresses a “relation to them collectively and vaguely”.
Strunk and White essentially concur.
The American Heritage Dictionary (my preferred non-legal dictionary) uses the following example: The bomb landed between the houses. It is implied that specific houses are identified and those houses define the precise boundaries within which the bomb landed. Whereas, in The bomb landed among the houses, the impact of the bomb is somewhere in the general location of a group of houses; the specific number of houses and their particular relationship to one another is not important.
Finally, again citing Garner, between expresses one-to-one relations of many things, whereas among expresses collective and undefined relations.
In a business contract, the parties are specific and the relationship between the parties is distinct – indeed foundational – to the document. Thus, I write that a contract is “between party A, party B, and party C”. The agreement is specifically between A and B, and A and C, and B and C. The contract is not just among a generalized and vague grouping of parties. It’s specific; the contract is between these exact parties and they each are agreeing with each of the other parties.
