What does it mean when the oil gauge says 80 on it?

80 is 80psi (pounds per square inch). Different model cars run different oil pressures, but 80psi is the very upper end of normal. Normal runs from 20psi to 80psi. I'd be a little concerned about a reading that high. If the pressure has increased from some low lower value I would take it to a mechanic.

You can try asking your question on the webpage in the link below. Be sure to give them the make, model and year of your car. I couldn't tell if they charge for answers.