Expressio unius
Contract Law

Expressio unius is an abbreviation of the full latin term expressio unius est exclusio alterius. This rule of construction (both in contracts and statutes) exists to import an intention into the interpretation of a contract that a reference to a particular person, power or thing excludes references to other to any other person, power or thing. The application of the rule assists to resolve ambiguity an uncertainty in contracts and statutes.

Thus, when a list of specific words are used with no general words following the specific list, the list is taken as exhaustive.

For instance, in a conveyance of copyright in computer software, may raise an issue of construction of the contract whereby the owner of the intellectual property rights did not intend to convey title to patent rights vesting in the software.  There is a limitation to the application of the maxim, in that the contract or other instrument may contain all the terms agreed between the parties.