reference point
point of reference
reference ***

He would land 15 feet to my right, using the light as his reference point.

These reference points come from a major part of their culture.

He is 35, though his cultural reference points are from the 50's.

You'll be our point of reference if we need to find you.

He was using his own hotel as a reference point.

The age given here is based on this reference point.

At the least, they provide a reference point to the player of his or her relationship with the game world.

We sort of like to keep it here as a reference point.

I tried to find a reference point on the ground north of us, but it was too dark.

And if you used a period about 10 years ago as a point of reference, that might be true.