Medical Definition of adhesive. 1: an adhesive substance; especially : a substance (as glue, starch, paste, or mucilage) that bonds two materials together by adhering to the surface of each.
The sensors physically measure the tire pressure in each tire and report it to the vehicle's instrument cluster or a corresponding monitor. Some units also measure and alert temperatures of the tire as well. These systems can identify under-inflation in any combination, be it one tire or all, simultaneously.
If you drive a newer car, you probably have what's called a Tire Pressure Monitoring System (TPMS) installed. TPMS is an electronic system inside the tire that monitors the air pressure in your tires. If your tires are under- or over-inflated, the TPMS activates a warning light on your dashboard. When the light is steady, it means you need to have your tire pressure checked.