Applicable law
Legal eagles will expend megawatts of intellectual energy scoping out, simply, what is meant by “law”. You might think it straightforward, but consider:
The multifarious sources of law: statutes and regulations of jurisdictions which do have practical control over the parties and their assets; common law, equity, and lesser constraints on one’s behaviour, such as stock exchange and clearing system rules, regulatory “guidance”; the rules and guidance of the Basel Committee on Bank Supervision, gentle but firm “requests” from regulators, and one can go yet further down the gears: one’s private contractual obligations (which are, after all, enforceable by the legal system) accounting principles, internal policies.
Then their applicability: there is a parallel multiverse, after all, of statutes and regulations and jurisprudence in jurisdictions which do not have, or claim, governance of the parties; laws that are in force and apply to the parties but are not relevant to the subject matter of the contract
All this in the service of delimiting what one’s contractual obligations should be.