Signpost (noun)

1. A post or board with a sign on it, indicating the direction and distance to various places.
2. A guide or indication of a direction or course of action.

Origin:

From the middle english signepost, from the old english sēnepost, from sēnep ("sign") + post ("post"). .

Examples:

1. We followed the signpost to the nearest town.
2. The company's financial losses were a signpost that they were headed for bankruptcy.
3. The signpost at the crossroads indicated that the left path led to the lake.
4. The new law is a signpost that the government is taking a tougher stance on crime.
5. The signpost on the trail showed us which direction to take to reach the summit.