APB (Advanced Peripheral Bus) IP is a reusable intellectual property (IP) block that implements the APB protocol for efficient communication with low-power peripherals. It simplifies the integration of devices like UARTs, timers, and GPIOs in SoCs by providing a simple, low-latency interface. APB IP ensures compliance with AMBA standards and supports easy interfacing with higher-performance buses like AHB or AXI through bridges.