Absolute pressure is pressure relative to a vacuum. The sensor has a vacuum chamber sealed inside as a reference—no matter how the outside atmospheric pressure changes, this reference is always «cero». So what you read is the true atmospheric pressure, which does not fluctuate with the weather. sensor that can sense absolute pressure and convert it into a usable output digital signal.
Traditional absolute pressure sensors output analog voltage signals, and you need to connect an amplifier circuit, an ADC, and perform temperature compensation, as well as calibrate them yourself. Digital absolute pressure sensors integrate all of these functions into the chip, so you get calibrated pressure values directly when you read them.