contemporanea expositio est optima et fortissima in lege
How a statute was understood and acted upon when it was passed, and shortly afterwards, by those administering it and by the courts, helps fix its meaning. The aid is most useful for old statutes with ambiguous words, where long and consistent practice shows how the words were taken.
Its limits are firm. It cannot override plain words, it carries less weight for recent statutes, and executive practice never binds the court. Departmental circulars and long administrative usage can be considered under it, but only as an external aid where the text leaves real doubt.
Example
Applying contemporanea expositio, the court relied on the uniform understanding of the 1950 rule by the department for decades to resolve the ambiguity.
In Indian law
See also
external aids to interpretation · literal rule · harmonious construction
Read more in the study notes
- External aids II: dictionaries, translations, statutes in pari materia, contemporanea expositio (Interpretation of Statutes and Principles of Legislation)