Expressio Unius Est Exclusio Alterius

Lat: The expression of one thing is the exclusion of another. In construing statutes, contracts, wills, and the like under this maxim, the mention of one thing within the statute or other document implies the exclusion of another thing not so mentioned. See 95 P. 2d 1007, 1012. "The maxim . . . Though not a rule of law, is an aid to construction. It has application when, in the natural association of ideas, that which is expressed is so set over by way of contrast to that which is omitted that the contrast enforces the affirmative inference that that which is omitted must be intended to have opposite and contrary treatment." See 34 So. 2d 132. Thus a statute granting certain rights to "police, fire, and sanitation employees" would be interpreted to exclude other public employees not enumerated from the legislation. This is based on presumed legislative intent and where for some reason this intent cannot be reasonably inferred the court is free to draw a different conclusion. See 16 N.E. 2d 459, 462.