A signpost.
Anything that provides guidance; a guideline.
A post bearing a sign that gives information on directions.
A word or phrase within a clue that serves as an indicator, rather than being fodder.
To indicate logical progress of a discourse using words or phrases such as now, right, to recap, to sum up, as I was saying, etc.
To install signposts on.
To signal, as if with a signpost
To direct (somebody) to services, resources, etc.