The definition of a pact is an agreement that is not to be broken.
(noun)See pact in Webster's New World College Dictionary
noun
Origin: OFr < L pactum, neut. of pactus, pp. of paciscere, to agree < base of pax, peace
See pact in American Heritage Dictionary 4
noun
Origin:
Origin: Middle English
Origin: , from Old French
Origin: , from Latin pactum
Origin: , from neuter sing. past participle of pacīscī, to agree; see pag- in Indo-European roots
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