did you pour the oil in the right hole?

did you drain the engine oil, or maybe something else like a differential?

How much oil did you put in?

There are really only two possibilities if there's really nothing on the dipstick, the oil either drained out or it was accidentally poured into the wrong place. Check all other fluids and don't try to start the engine until you know what's going on.

I once had a Volvo on which I needed to remove the dipstick and insert again to get an oil reading - that was due to a bad PVC valve.

Also are you sure you added it to the engine?

are you sure you have inserted the dipstick correctly? - see visually that it goes into the right hole

Did you ever see the oil full after the last replacement?

Anyhow, perhaps you didn't pour in enough oil - that car was offered with 3 different engines, each one with its oil capacity, (I think the 4 cyls had just a bit under 5 quarts and the V6 with a bit over 5 quarts) I think you can add more and see if it appears. At worst if you discover you added too much you'll just pour out.

If you can not figure it out, don't start the engine - go to a mechanic.

If it has "disappeared" and especially if you have the 2.4L, it maybe due to the 2.4L burning oil like there's no tomorrow. 

Try wiping it on a clean surface. When there's brand new oil in the system, it's almost clear, unless you have quarts of it. 

Have you personally changed the oil and filter in this vehicle before and been able to accurately determine the oil level on the dipstick?

Put same amount of engine oil as suggested (5qts minus enough for the 505) - added a couple more and still no reading. Definitely in the right hole.

Just wondering if a piece of sludge may have created a clog?