The institution of government that interprets laws made by the legislature is

The institution of government responsible for interpreting laws made by the legislature is the judiciary. Under the doctrine of separation of powers, the three arms of government have distinct functions:

• The legislature makes laws.
• The executive implements and enforces laws.
• The judiciary interprets laws and adjudicates disputes.

The judiciary, through its system of courts, determines the meaning and application of laws passed by the legislature. It resolves conflicts between individuals, between individuals and the state, and between different levels of government. In Nigeria, the judiciary is headed by the Supreme Court, with the Court of Appeal, Federal High Court, State High Courts, and other specialised courts beneath it.

The judiciary also exercises the power of judicial review, which allows courts to examine whether laws or executive actions are consistent with the constitution and to declare them void if they are not.

Senators are individual members of the upper legislative chamber (the Senate) - they are part of the legislature, not a separate institution. They participate in law-making, not law interpretation.