Approval, or permission to proceed.
A go-ahead to commit a crime, specifically to carry out a hit on someone (i.e. to kill).
A traffic light in its green state (indicating that vehicles may proceed).
To use a veto against.
An invocation of that right.
A technique or mechanism for discarding what would otherwise constitute a false positive in a scientific experiment
A political right to disapprove of (and thereby stop) the process of a decision, a law etc.
An authoritative prohibition or negative; a forbidding; an interdiction.